Effective suppression of ovarian cyclicity in the lowland gorilla with an oral contraceptive

To determine the effects of a human oral contraceptive on normal and abnormal reproductive endocrine patterns in two lowland gorillas (Gorilla gorilla), daily urine samples were analyzed by radioimmunoassay for estrone conjugates (EC) and pregnanediol-3-glucuronide (PdG). During a pre-treatment period one female (F1) demonstrated regular menstrual cycles averaging 27.6 ± 1.8 days, whereas ovarian cyclicity in female 2 (F2) was consistently prolonged, ranging from 37–51 days. A 56 day regimen of an oral contraceptive (Demulen 50®) was administered to both females beginning in the late luteal phase, and within 6 and 7 days of treatment onset (F1 and F2, respectively) urinary EC and PdG declined to and remained at concentrations consistent with amenorrhea throughout the administration period. Ten and twenty days after contraceptive withdrawal (F1 and F2, respectively) an EC peak was observed with subsequent PdG elevations 1–2 days later. Mean cycle length and luteal phase durations were not different (P > 0.05) before or after treatment for either female, while combined peak PdG concentrations were greater (P < 0.05) for the first 3 months after treatment compared to pre-treatment values. These results indicate that a human oral contraceptive rapidly suppresses ovarian activity in female lowland gorillas, but that the abnormal endocrine pattern observed in F2 could not be redirected into a normal profile after contraceptive withdrawal. © 1992 Wiley-Liss Inc.     

Urinary steroid evaluations to monitor ovarian function in exotic ungulates: II. Comparison between the giraffe (Giraffa camelopardalis) and the Okapi (Okapia johnstoni)

Ovarian activity in the female giraffe was evaluated during the nonfertile ovarian cycle and during the terminal stages of gestation. Progesterone metabolites, in the form of pregnanediol-3-glucuronide (PdG), were measured in daily random urine samples collected from four adult parous giraffes. The follicular phase averaged 4.0 ± 0.1 days in length (N = 12; range 3–5 days) and peak PdG levels in the postovulatory period averaged 30.9 ± 1.7 ng/mg Cr (N = 12). PdG levels during the latter half of gestation greatly exceeded average luteal phase levels, which is in contrast to domestic ruminants. Prior to parturition, a marked decline in PdG excretion was evident, which may be useful for anticipating this event. These data serve to elucidate ovarian function in the mature female giraffe and to provide information concerning the physiologic role of certain anomalous ovarian structures. In addition, observed similarities in the pattern of PdG excretion during the nonfertile cycles of the giraffe and the okapi indicate similar underlying physiologic processes.     

Endocrine monitoring of the ovarian cycle and pregnancy in the saddle-back tamarin (Saguinus fuscicollis) by measurement of steroid conjugates in urine

Direct measurements of urinary immunoreactive estrone conjugates (E1C) and pregnanediol glucuronide (PdG), were applied to monitoring the ovarian cycle (n = 9) and pregnancy (3 full term pregnancies, 2 mid-term abortions) in Saguinus fuscicollis. During the ovarian cycle, urinary E1C concentrations revealed a high degree of day-to-day variability and appeared to be uninformative in reflecting cyclic ovarian function. In contrast, PdG was a reliable indicator of ovarian cyclicity with excretion patterns corresponding well with plasma progesterone profiles. Luteal phase PdG concentrations were on average 4–7–fold higher than corresponding follicular phase values. On the basis of changes in circulating progesterone, a mean cycle length of 25.7 ±1.0 days with an average follicular phase of 7.1 ± 0.6 days and a mean luteal phase of 18.6 ± 0.7 days, was found (n = 14 cycles). Following conception, both urinary steroid conjugate concentrations increased and elevated levels were maintained beyond the normal luteal phase length, allowing pregnancy to be determined at around day 25–30. During mid- to late pregnancy, PdG levels declined while E1C concentrations continued to be elevated until approximately 6 weeks before parturition when a decrease occurred. Both hormones showed a clear and rapid fall to follicular phase values following termination of pregnancy at either parturition or mid-term abortion. Post partum ovulations (n = 5) occurred on average 17–18 days following birth with four ovulations leading to conceptions. The results demonstrate the potential of urinary steroid conjugate analysis as a practical and reliable method for non-invasive monitoring of reproductive status in the female saddle-back tamarin. © 1995 Wiley-Liss, Inc.     

Long-term data on basic reproductive parameters and evaluation of endocrine,morphological, and behavioral measures for monitoring reproductive status in a group of semifree-ranging Tonkean macaques (Macaca tonkeana)

Cycle and gestation lengths, menstruation patterns, female genital swelling characteristics, and male-female consortship durations are reported in a semifree-ranging group of Tonkean macaques (Macaca tonkeana) studied over a 12 year period. In addition, profiles of urinary estrone conjugates (E1C) and immunoreactive pregnanediol glucuronide (PdG) throughout four complete menstrual cycles in two females and three full-term pregnancies are presented. Based on intermenstrual intervals, a mean cycle length of 37–41 days (n = 55 cycles in 10 females) was found. Gestation length averaged 173 days (n = 27 pregnancies in eight females). Measurement of PdG immunoreactivity in urine revealed a cyclic pattern with a 5–15-fold increase between follicular and luteal phase concentrations, suggesting that PdG is a reliable indicator of ovarian cyclicity and luteal function. In contrast to PdG, E1C excretion showed no clear pattern throughout the cycle; however, highest values of E1C were usually found shortly before the onset of the luteal phase PdG rise at the presumed time of ovulation. Levels of both hormones were elevated during the first half of gestation and showed a marked increase throughout the second half, with maximum E1C concentrations being up to 100-fold higher than nonpregnant levels. Consortships by the male and occurrence of female genital swelling were long lasting (on average 5–10 days and 13 days, respectively) and were restricted to the follicular phase of the cycle. The day of maximal swelling and day of detumescence as well as the end of male consortship were closely associated with the periovulatory period. Swellings and consortships were longer following lactational ammenorhea than for subsequent cycles. The evolutionary significance of the cyclical changes undergone by females upon their relations with males is discussed. © 1996 Wiley-Liss, Inc.     

Assessment of ovarian function in the African elephant (Loxodonta africana) by measurement of 5α-reduced progesterone metabolites in serum and urine

We have previously shown that 5α-pregnane-3,20-dione (5αDHP), and 5α-pregnane-3-ol-20-one (5α-P-3-OH) are the major luteal and circulating progestins in the African elephant. Therefore, the aim of the present study was to determine (1) circulating levels and patterns of secretion of 5α-DHP in relation to progesterone (P4) throughout the ovarian cycle, (2) the presence and relative abundance of 5α-reduced progestins in urine and (3) whether their measurement in urine would provide a non-invasive method for monitoring luteal function. Urine samples were collected weekly throughout a total of 13 ovarian cycles from 5 females. In addition, matched blood samples were collected during 6 cycles from 2 of the 5 animals. All hormone measurement, were carried out by enzymeimmunoassay following extraction. Urine was hydrolyzed prior to extraction. Profiles of P4 and 5α-DHP in serum followed a similar cyclic pattern and both measurements were significantly correlated (r = 0.78–0.98, mean 0.89, P < 0.001). Concentrations of 5α-DHP were, however, 10–20 fold higher than those of P4. I addition, 5α-DHP measurements showed a more pronounced luteal phase increase than that of immunoreactive P4. HPLC co-chromatography confirmed the presence of large amounts of 5α-P-3-OH in urine as a single immunoreactive peak, whereas 5α-DHP was present in very low levels and measurable only as one of several immunoreactive substances. Measurements of urinary 5α-P-3-OH were significantly correlated to serum 5α-DHP measurements in each of the 6 cycles (r = 0.72–0.93, mean 0.81, P < 0.001), whereas correlation coefficients between urinary and serum 5α-DHP values were generally lower (r = 0.34–0.83, mean 0.69) and significant in only 4 of the 6 cycles. Accordingly, only urinary excretion of 5α-P-3-OH, but not of 0.15–0.20 μ/mg Cr in the follicular phase and 10-fold elevated levels (1.8–2.2 μg/mg Cr) in the luteal phase. Based on the intervals between successive luteal phase increases in urinary 5α-P-3-OH, a mean cycle length of 14.1 ± 1.8 weeks, comprising a follicular phase of 5.0 ± 0.9 weeks and a luteal phase of 9.1 ± 1.4 weeks was determined for the 13 cycles studied. The results indicate that measurements of 5α-P-3-OH in urine provide a reliable non-invasive method for monitoring luteal function in the African elephant. Zoo Biol 16:273–284, 1997. © 1997 Wiley-Liss, Inc.     

Assessment of female reproductive status in captive-housed Hanuman langurs (Presbytis entellus) by measurement of urinary and fecal steroid excretion patterns

The study reports on the use of urinary and fecal hormone measurements for monitoring female reproductive status in captive-housed Hanuman langurs (Presbytis entellus). Matched urine and fecal samples collected throughout 7 complete menstrual cycles of two females, and during part of one pregnancy in a third female were analyzed. Estrone conjugates (E1C) and immunoreactive pregnanediol glucuronide (PdG) in urine and immunoreactive estradiol (E2), progesterone (P4), pregnanediol (Pd) and 20α-hydroxyprogesterone (20αOHP) in feces were measured by enzymeimmunoassay. E1C and PdG in urine were excreted in a cyclic pattern with E1C levels increasing 3- to 4-fold during the follicular phase to reach preovulatory peak values 2 days before a defined rise in PdG concentrations. Cycle lengths ranged between 20 and 34 days comprising a variable follicular phase of 7–21 days and a more consistent luteal phase of 12–14 days. High pressure liquid chromatography (HPLC) analysis of fecal extracts confirmed the presence of all fecal hormones measured, but indicated large amounts of additional immunoreactivity in the three progestin assays. The patterns of excretion of fecal E2 and all three fecal progestins corresponded well with those of steroid metabolites in urine in showing a clear and well defined follicular phase E2 rise followed by a luteal phase progestin increase. Measurement of 20αOHP immunoreactivity revealed the most stable baseline and the highest follicular/luteal phase differential. Levels of all hormones were clearly elevated during pregnancy although urinary E1C and PdG showed a more pronounced increase compared to fecal metabolites. The results indicate that urinary and fecal hormone analysis can be applied to noninvasive monitoring of reproductive status in the Hanuman langur. © 1995 Wiley-Liss, Inc.     

Sexual and Hormonal Cycles in Geriatric Gorilla gorilla gorilla

As our closest living relatives, great apes likely experience behavioral and physiological patterns associated with reproductive aging and menopause that are similar to human patterns. We present results from a nationwide zoo-based study on behavioral and hormonal changes in female western gorillas. We evaluated progestogen concentrations via daily fecal sampling in 30 gorillas, 22 of which were geriatric (≥30). We collected concurrent behavioral data 1–3 times weekly on 16 of the females. While control females cycled regularly, ca. 23% of geriatric females are acyclic (menopausal), and another 32% show variable hormonal patterns suggesting perimenopause. Patterns included increased variability in cycle length and peak progestogen values, and frequent insufficient increases in progestogen levels during the luteal phase. Acyclic females have significantly lower overall progestogen concentrations than the self cycling females, though differences are not significant when cycle phase is incorporated. We detected behavioral estrus in 9 of 10 cycling females for which data were available. In all but 1 case, proceptive behavior occurred during the follicular phase, preceding ovulation on average by 6.6 d. Females spent more time in proximity to the silverback male while in behavioral estrus than during other periods. To date, maximum longevity in captive female gorillas is 52 yr, with poor reproductive prognosis beginning from the age of 37. We demonstrate that both perimenopause and menopause characterize aged female gorillas, which may experience a postreproductive lifespan of >25% of their lives. Continued study of aging apes is warranted, and apes may serve as models for age-related reproductive changes in humans.     

Endocrine profiles during the estrous cycle and pregnancy in the Baird's tapir (Tapirus bairdii)

Serum samples were collected 1–3 times weekly from two Baird's tapirs (Tapirus bairdii) for 6 months in 1987–1988, and for more than 3 consecutive years beginning in 1989 to characterize hormone patterns during the estrous cycle and pregnancy. Based on serum progesterone concentrations, mean (±SEM) duration of the estrous cycle (n = 20) was 30.8 ± 2.6 days (range, 25–38 days) with a luteal phase length of 18.1 ± 0.4 days (range, 15–20 days). Mean peak serum progesterone concentrations during the luteal phase were 1.35 ± 0.16 ng/ml, and nadir concentrations were 0.19 ± 0.03 ng/ml during the interluteal period. Distinct surges of estradiol preceded luteal phase progesterone increases in most (14/20) cycles. Gestation length was 392 ± 4 days for three complete pregnancies. Mean serum progesterone concentrations increased throughout gestation and were 1.83 ± 0.13, 2.73 ± 0.13, and 4.30 ± 0.16 ng/ml during early, mid- and late gestation, respectively. Serum estradiol concentrations began to rise during mid-gestation, increasing dramatically during the last week of pregnancy. Patterns of serum estriol and estrone secretion during pregnancy were similar to that observed for estradiol. In contrast to progesterone and estrogens, serum cortisol concentrations were unchanged during pregnancy or parturition. Females resumed cycling 16.2 ± 2.0 days after parturition (n = 4) and, on two occasions, females became pregnant during the first postpartum estrus. These data suggest that the tapir cycles at approximately monthly intervals and that increases in serum progesterone are indicative of luteal activity. The interluteal period is relatively long, comprising approximately 40% of the estrous cycle. During gestation, progesterone concentrations are increased above luteal phase levels, and there is evidence of increased estrogen production during late gestation. The absence of increased cortisol secretion at the end of gestation suggests that this steroid does not play a major role in initiating parturition in this species. © 1994 Wiley-Liss, Inc.     

Plasma gonadotrophin and ovarian steroid concentrations in women with menstrual cycles with a short luteal phase

Daily plasma concentrations of FSH, LH, oestradiol-17 beta and progesterone were compared for 12 cycles with a short luteal phase and 19 cycles with a luteal phase of normal length (i.e. cycles in which the luteal phase lasted 12 or more days). FSH and LH concentrations were suppressed in short luteal-phase cycles in the early follicular phase and the length of the follicular phase was prolonged (median duration, 14.5 days, range 13-21 days: compared with 12 days, range 9-17, in control cycles; P less than 0.025). Preovulatory oestradiol-17 beta values and the mid-cycle concentrations of FSH and LH were similar in both groups. Plasma progesterone values in the luteal phase were similar in both groups over the 2nd to 5th days inclusive after the midcycle LH peak but declined in the short luteal phases thereafter. In short luteal-phase cycles, menstruation occurred in the presence of higher levels of oestradiol-17 beta and progesterone than in cycles of normal length and the rise of gonadotrophin in the late luteal phase of the cycle was delayed. These findings suggest that in cycles with a short luteal phase there is a lack of synchrony between the ovarian and menstrual events.     

Oestrous cycle of the North American bison (Bison bison) characterized by urinary pregnanediol-3-glucuronide.

An enzyme immunoassay for urinary pregnanediol-3 alpha-glucuronide (PdG) was evaluated for the indirect measurement of progesterone metabolites during the oestrous cycle and early pregnancy of uncaptured North American bison. Comparisons between plasma progesterone and urinary PdG, dose-response parallelism between the standard curve and diluted urine samples and high-performance liquid cochromatography revealed that PdG was a primary immunoreactive urinary metabolite of progesterone in bison. Urine samples were collected directly from the soil from 29 bison cows during the August rutting season and analysed for PdG. Eight bison cows demonstrated complete oestrous cycles ranging from 19 to 26 days (mean cycle length = 23.12 +/- 0.76 days) and behavioural oestrus among four of these cows correlated with PdG nadirs. Mean PdG nadirs were 63.62 +/- 21.61 ng/mg urinary creatinine (Cr) and mean peak midluteal values were 546.01 +/- 130.73 ng/mg Cr. Seven of eight became pregnant, indicating that bison exhibit a second seasonal oestrus. Eighteen other bison cows were pregnant prior to the beginning of the study and demonstrated non-cyclic increased PdG concentrations (greater than 200 ng/mg Cr) during the 30-day course of collection. Three cows ovulated and became pregnant during the 30-day collection period and then exhibited increasing urinary PdG concentrations. This report demonstrates that ovarian function in uncaptured bison can be monitored by means of urinary PdG and that both ovulatory cycles and early pregnancy can be detected.     

Urinary steroid and gonadotropin excretion across the reproductive cycle in female Wied's black tufted-ear marmosets (Callithrix kuhli)

Details of the endocrinology of reproduction in the genus Callithrix are known only for the common marmoset, C. jacchus. This paper presents the patterns of urinary pregnandiol-3-glucuronide (PdG), urinary estrone conjugates (E₁C), and gonadotropin excretion throughout the reproductive cycle of Wied's black tufted-ear marmoset (C. kuhli) as determined via steroid conjugate enzyme immunoassays (EIA) and gonadotropin radioimmunoassays (RIA). Postpartum ovulation occurred at 13.6 ± 1.2 days after parturition (n = 12) and was characterized by low PdG and E₁C concentrations accompanied by a spike in luteinizing hormone (LH)/chorionic gonadotropin (CG) concentration. After conception, PdG concentrations increased dramatically until they dropped to periovulatory concentrations in the third trimester of pregnancy. Mean PdG concentrations in the first and second trimesters (33.7 ± 8.4 and 39.0 ± 10.9 μg/mg creatinine, respectively) were three times that of third trimester concentrations (11.7 ± 1.4 μg/mg Cr; n = 8). Urinary concentrations of E₁C rose more gradually during pregnancy and remained higher prepartum than urinary concentrations of PdG. Urinary gonadotropin concentrations also increased after conception (first trimester concentrations = 24.5 ± 4.5 ng/mg Cr) and continued to increase in the second trimester (51.4 ± 7.6 ng/mg Cr), until they finally decreased in the third trimester (mean = 7.9 ± 1.4 ng/mg Cr; n = 8). The interbirth interval was 156.3 ± 2.9 days (n = 6), with a gestation of 143.1 ± 1.6 days (n = 8). Nonconceptive cycle length was 24.9 ± 0.6 days (n = 4). The results of this study suggest strong similarities in reproductive parameters in the genus Callithrix. © 1996 Wiley-Liss, Inc.     

Probably never human. Review of chimpanzee material culture: Implications for human evolution,by W.C. McGrew. Cambridge,U.K., Cambridge University Press, 1992, 277 pp, $79.95, cloth

Pregnanediol-3α-glucuronide (PdG) was measured in the urine of six Goeldi's monkeys during pregnancy and the postpartum period. A stress-free, non-invasive urine sampling technique permitted frequent collection of urine from members of the breeding group. A comparison of the periovulatory profiles of PdG and estrone conjugates revealed close agreement. The day of ovulation was defined as that immediately preceding a 2-4 day period with two consecutive urine samples for which the PdG content was in excess of 0.20 μg/mg Cr and 0.40 μg/mg Cr, respectively. In urine samples collected from parturition to the next ovulation, 70.9% of the PdG-values were below 0.20 μg/mg Cr, whereas 99.2% of the urinary PdG concentrations measured during pregnancy were greater than this “threshold concentration”. A conception cycle was therefore defined as one in which the concentration of urinary PdG remained above 0.20 μg/mg Cr in all urine samples collected between day 1 and day 20 after ovulation. Gestation length was 151.5 ± 1.6 days (mean ± SEM, n = 6; range 147-157 days). The postpartum ovulation occurred 22.6 ± 4.7 days (mean ± SEM, n = 9; range 11-53 days) following birth. With the exception of two non-conception postpartum cycles observed in one female, with inter-ovulatory intervals of 26 and 27 days, postpartum ovulation resulted in conception, giving a 77.8% conception rate for nine observed cycles. The simple and rapid radioimmunoassay used in this study requires 5 h from urine collection to the final result, hence permitting daily monitoring of a large sample of females. It thus has important potential for conservation breeding programs and for other scientific investigations carried out with this endangered primate species. © 1994 Wiley-Liss, Inc.     

Describing Ovarian Cycles,Pregnancy Characteristics,and the Use of Contraception in Female White‐Faced Marmosets,Callithrix geoffroyi

Endocrine data and characteristics of nonconceptive ovarian cycling and pregnancy are limited within the genus Callithrix to the common marmoset (C. jacchus) and Wied's black tufted‐ear marmoset (C. kuhlii). This article presents patterns of urinary pregnanediol‐3‐glucuronide (PdG) excretion, as determined by enzyme immunoassay, throughout the course of ovarian cycling and pregnancy in white‐faced marmosets (C. geoffroyi). Furthermore, characteristics of reproductive parameters including litter size, duration of gestation, maternal age, and information about ovarian cycling following administration of contraceptives are also described. A steep increase in PdG, an indication of ovulation, characterizes normative ovarian cycles, with peak‐to‐peak intervals between cycles being 27.82 ± 1.49 days in length. PdG excretion (μg/mg Cr) across pregnancy peaked during the 1st and 2nd trimesters (1st = 20.71 ± 2.98, 2nd = 21.16 ± 2.60) and declined gradually to near preconception levels over the 3rd trimester until parturition (3rd = 5.74 ± 1.60). Gestation lasted 148.55 ± 1.89 days. Most pregnancies (82.8%) resulted in an immediate postpartum ovulation (PPO) of 17.45 ± 2.22 days with 58.3% of PPOs resulting in conception. No differences in PdG excretion during the 1st trimester between full pregnancies and miscarriages were found, and pregnancy characteristics such as litter size, duration of gestation, and maternal age were not associated with PdG concentrations. Administration of cloprostenol resulted in shorter peak‐to‐peak cycle durations, but ovulation was detectable with similar concentrations of peak PdG to a normal nonconceptive cycle. Conversely, medroxyprogesterone acetate (DMPA) injections resulted in little to no PdG excretion across the ovarian cycle. Both methods of contraception providing effective prevention of conception. Overall, these results show that strong similarities in reproductive parameters persist within the genus Callithrix and to a lesser extent across the Callitrichidae family. Am. J. Primatol. 74:1044‐1053, 2012. © 2012 Wiley Periodicals, Inc.     

Comparative study of urinary reproductive hormones in great apes

Urinary estrone conjugates (E₁C), pregnanediol-3-glucuronide (PdG), and follicle-stimulating hormone (FSH) were determined by enzyme immunoassays (EIAs) during the normal menstrual cycle in the orangutan, gorilla, chimpanzee, and bonobo. Furthermore, the data were compared to those levels in the human and long-tailed macaque. The results showed a typical preovulatory E₁C surge and postovulatory increase in PdG in all species. The pattern of E₁C during the menstrual cycle in the great apes more closely resembled the human than do the long-tailed macaque. A major difference of E₁C pattern between these species appeared in the luteal phase. In the great apes and the human, E₁C exhibited two peaks, the first peak detected at approximately mid cycle and the second peak detected during the luteal phase. On the other hand, in the long-tailed macaque, increase of E₁C in the luteal phase was small or nonexistent. The gorilla, chimpanzee, and bonobo exhibited similar PdG trends. The orangutan excreted one tenth less PdG than these species during the luteal phase. The long-tailed macaque also excreted low levels of PdG. The patterns of FSH in orangutan, chimpanzee, bonobo and long-tailed macaque showed a marked mid-cycle rise and an early follicular phase rise, similar to those in the human. Comparing similar taxa, a large difference was found in FSH of gorilla; there were three peaks during the menstrual cycle. Thus, there is considerable species variation in the excretion of these hormones during the menstrual cycle and comparative studies could be approached with a single method. The methods and baseline data presented here provide the basis for a practical approach to evaluation and monitoring of ovarian events in the female great apes. Electronic Publication     

Analysis of urinary immunoreactive steroid metabolites and gonadotropins for characterization of the estrous cycle,breeding period,and seasonal estrous activity of captive killer whales (Orcinus orca)

To increase the basic understanding of killer whale (Orcinus orca) reproductive physiology necessary for the development of artificial breeding programs, we utilized radioimmunoassays (RIA) to detect urinary immunoreactive steroid metabolites (pregnanediol-3α-glucuronide [PdG] and estrone-conjugates [EC]) and gonadotropins (luteinizing hormone [LH] and follicle-stimulating hormone [FSH]) in urine samples from six female killer whales. Urine samples were collected from the whales by voluntary presentation behavior over a 2- to 4-year period. All urinary hormone values were corrected for intersample urine concentration variations by indexing with creatinine. Daily urine samples from four whales were collected during two conceptions and 18 complete estrous cycles. LH, FSH, EC, and PdG immunoreactive levels were determined and combined with observed copulatory activity in five cycles, including two conceptive cycles from two whales. Mean luteal phase lengths ranged from 9.7 to 19.2 days. Mean follicular phase lengths ranged from 6.5 to 16.8 days. Mean estrous cycle lengths based on the first detectable PdG levels were 41.6 ± 6.72 S.E.M. days. After PdG nadir, immunoreactive FSH levels showed a bimodal pattern with the first peak being greater in size, and both preceding a follicular phase EC increase. LH levels > the 95% confidence interval of the mean were considered significant. Combined LH immunoreactive values from whales 2 and 6 during two and three estrous cycles, respectively, had significant LH peak concentrations on day minus 2. These significant LH peaks were assumed to represent the preovulatory LH surge. Eight copulations during two conceptive cycles were observed between whales 2 and 6 and a breeding male. Six of these copulations (3 with each female whale) occurred within 72 hours of the beginning or the end of the presumptive preovulatory LH surge. Estrous activity was seen throughout the year for the herd. However, individuals had varying periods of anestrus that could not be linked to environmental, social, or nutritional influences. The whales that were reproductively successful had anestrus intervals that were usually influenced by gestation, postparturient period, or lactation. The information obtained during this research enhances the foundation for future artificial reproductive management techniques. © 1993 Wiley-Liss, Inc.     

Changes of urinary steroid conjugates and gonadotropin excretion in the menstrual cycle and pregnancy in the Yunnan snub-nosed monkey (Rhinopithecus bieti).

The Yunnan snub-nosed monkey (Rhinopithecus bieti) is one of the most endangered species in the world, and it is endemic to China. According to our knowledge, there was no information on reproduction for this species. The present study was designed to understand the characteristics of reproductive hormone secretion during the menstrual cycle and pregnancy of this species by monitoring urinary estrone conjugate (E1C), pregnanediol-3-glucuronide (PdG), bioactive follicle-stimulating hormone (FSH), and luteinizing hormone (LH). The urine samples were collected each day from four adult females for eight menstrual cycles, and once in 3 days during pregnancy (three full-term pregnancies, one mid-term abortion). The steroid conjugate was tested by radioimmunoassays (RIAs), and bioactive FSH and LH levels were measured in vitro by the sensitive bioassays granulosa cell aromatize bioassay (GAB) and rat interstitial cell testosterone (RICT), respectively. The results showed that: 1) E1C presented a preovulatory peak (183.9 +/- 8.6 ng/mgCr) followed by a definite elevation of PdG; 2) PdG in the luteal phase (754.4 +/- 30.6 ng/mgCr) was three- to fivefold higher than during the corresponding follicular phase (198.3 +/- 11.4 ng/mgCr); 3) the peaks of bio-LH and bio-FSH were on the same day, while the E1C peak was 1 or 2 days before the peaks for these two hormones; 4) bio-FSH levels were higher in the follicular phase than in the luteal phase, and bio-LH levels elevated slightly in the luteal phase; 5) the mean cycle length was 23.6 +/- 3.5 days (n = 3) based upon successive urinary LH peaks; 6) based on the interval from the day of E1C peak to the day of parturition, the gestation was 203.7 +/- 2.5 days (n = 3); and 7) both E1C and PdG increased and remained high after pregnancy, with a sharp decrease in basal levels following parturition or mid-term abortion. The results suggested that the pattern of reproductive hormones for R. bieti is similar to that of other Old World monkeys, but the concentration of the hormones is different from that of other species. This species has a longer progestation period, which may be related to its classification status.     

Reproductive,behavioral, and endocrine characteristics of the Dall's sheep (Ovis dalli dalli)

Failed interspecific embryo transfer between Dall's sheep (Ovis dalli dalli) and domestic ewes (Ovis aries), and a paucity of physiological data available for the Dall's sheep, provided incentive for developing a reproductive database in Dall's sheep. Urine samples were collected on a regular basis from a captive herd of Dall's sheep during the breeding to lambing interval over a 3 year period. To provide comparative endocrine data during pregnancy, samples also were collected during a single gestation period from five Suffolk ewes. All urine samples were analyzed for pregnanediol-3-glucuronide (PdG) and estrone conjugates (EC). Behavioral observations from Dall's sheep were made each year during the rut and lambing periods to calculate estrous cycle and gestation lengths. Placentas from Dall's sheep (n = 20) and Suffolk ewes (n = 10) were collected, the total number of cotyledons counted, and the length, width, area, and weight of eight cotyledons/horn from each placenta calculated. Endocrine and behavioral results indicated that the Dall's sheep is seasonally polyestrous and monovulatory, with a mean estrous cycle length of 18.2 ± 0.3 days, a mean luteal phase of 11.8 ± 0.5 days, and an average gestation length of 171.6 ± 0.9 days. While hormonal patterns for pregnancy generally were similar between the two species, there was a pronounced difference in the magnitude of hormone concentrations, particularly PdG, and an absence of a marked preparturition EC rise in domestic sheep. Cotyledon numbers, weight, and area were smaller (P < 0.05) in the Dall's sheep, compared to Suffolk ewes. These data suggest that unsuccessful interspecies embryo transfer attempts may have been due to failed fetal/maternal communications resulting from hormonal and/or placental differences. © 1996 Wiley-Liss, Inc.     

Reproductive endocrine responses to photoperiod and exogenous gonadotropins in the pallas' cat (Otocolobus manul)

Fecal samples were collected for 14–26 months from three male and six female Pallas' cats (Otocolobus manul) to examine gonadal steroidogenic activity in response to changes in photoperiod and treatment with exogenous gonadotropins. Females exhibited a seasonal anestrus from May–December, excreting consistently low concentrations of fecal estrogens (overall mean, 50.2±8.5 ng/g). During the breeding season (January–April), baseline fecal estrogen concentrations were higher, averaging 128.4±18.9 ng/g, with peak concentrations ranging from 455.8–909.6 ng/g. Interpeak intervals in estrogen excretion ranged between 7 and 21 days, with an average estrous cycle length of 14.3±1.7 days. Two females became pregnant after natural mating, with overall luteal progestogen concentrations averaging ～40 μg/g throughout gestation. Fecal estrogens increased in mid‐gestation, peaking just before birth. Induction of follicular development with eCG (100–300 IU, i.m.) resulted in an increase in fecal estrogens (peak range, 263.1–1198.1 ng/g), followed by a postovulatory increase in fecal progestogens (overall mean, 41.1±11.9 μg/g) after hCG (75–150 IU, i.m.). Despite apparently normal ovarian responses, none of the females conceived after artificial insemination (AI). The gonadotropin‐induced nonpregnant luteal phase lasted 49.8±5.3 days (range, 30–60 days), whereas gestation lasted ～70 days. In the male Pallas' cat, fecal androgens were elevated from November–April (overall mean, 352.3±30.3 ng/g) compared with nadir concentrations during the rest of the year (82.1±3.3 ng/g). Entrainment of seasonality to photoperiod was demonstrated by stimulation of gonadal steroidogenic activity in cats exposed to increasing artificial light during natural (nonbreeding season) and artificially induced short‐day photoperiods. In summary, reproduction in Pallas' cats is highly seasonal and photoperiod‐dependent. Females exhibit elevated baseline and peak fecal estrogen concentrations for 3–4 months during late winter/early spring. Testicular steroidogenic activity precedes the rise in female estrogen excretion by about 2 months, presumably to ensure maximal sperm production during the breeding season. Zoo Biol 21:347–364, 2002. Published 2002 Wiley‐Liss, Inc.     

Monitoring ovarian function in scimitar-horned oryx (Oryx dammah) by measurement of fecal 20α-progestagen metabolites

The feasibility of monitoring ovarian function in scimitar-horned oryx (Oryx dammah) by measurement of fecal 20α-progestagens was investigated. Fecal samples were collected daily or on alternate days over a 4–11 month period from five oryx during natural (n = 4) or synthetic PGF_2α (cloprostenol)-controlled (n = 1) cycles. Of the four oryx undergoing natural cycles, three had regular access to a vasectomised male, and mating dates were recorded. Ultrasonography was used to monitor changes in reproductive tract morphology in the female administered with cloprostenol. Neutral steroids were extracted from feces with methanol:petroleum ether (2:1 v/v) after first removing phenolic steroids with potassium hydroxide (1 M). The concentration of 20α-progestagens in the methanol phase was measured by enzymeimmunoassay. Excretion of 20α-progestagens in all females followed a cyclic pattern corresponding to the follicular and luteal phases of the ovarian cycle. Concentrations of fecal 20α-progestagens were on average twentyfold greater during the luteal phase compared with the follicular phase. Mean (±SD) ovarian cycle length, based on fecal progestagen profiles, was 24.4 ± 2.2 days with mean (±SD) luteal and follicular phase lengths of 18.7 ± 2.8 and 5.7 ± 1.6 days, respectively. Mating by a vasectomized male occurred when 20α-progestagen concentrations were still elevated or declining. Similarly, fecal progestagens did not return to follicular phase concentrations for 4–5 days after administration of cloprostenol, and a 4 day delay was observed between ovulation, as visualized by ultrasound scanning, and a rise in fecal 20α-progestagens. These data suggest a time lag of approximately 4 days between reproductive events and changes in fecal 20α-progestagen concentrations. We conclude that measurement of immunoreactive 20α-progestagen concentrations in feces has limited application for predicting ovulation or accurately timing inseminations because of delay in steroid excretion, but will enable noninvasive monitoring of ovarian cycles in scimitar-horned oryx for fertility assessment and for determining the outcome of artificial insemination programs. © 1995 Wiley-Liss, Inc.     

Use of salivary steroid analyses to assess ovarian cycles in an Indian rhinoceros at the National Zoological Park

Saliva samples were collected from a female Indian rhinoceros (Rhinoceros unicornis) housed at the National Zoological Park, and ether-extracted for analyses of androgen, estrogen, and progestin metabolites to assess ovarian cycles. Analyses of both salivary androgens and estrogens were found to reliably monitor follicular activity. Although the temporal patterns of the two steroids were significantly correlated (r=0.62; P<0.05), they differed slightly. Salivary androgens increased earlier during the follicular phase, although both peaked at the same time in association with behavioral estrus. Based on salivary androgen profiles, the mean duration of the follicular phase was 11.4 days (ranged=7–15 days; n=17 cycles). Estrous cycle length, as measured by the time between consecutive androgen peaks, was 47.4±3.4 days (range=37–86 days). Salivary progestin measurements were effective for monitoring luteal function. The mean duration of the luteal phase was 15.5±1.5 days (range=10–23 days). In sum, assays were identified for measuring salivary steroids to assess ovarian function in Indian rhinoceroses. However, not all of the assay systems tested were effective, perhaps because of interfering matrix effects. Mate introductions in the Indian rhinoceros often require careful monitoring, and a technique for monitoring hormones in saliva could be an alternative to urine or fecal analyses for identifying estrus and timing breeding in this species. Such a technique would be particularly useful for situations in which it is difficult to collect uncontaminated urine and feces. Zoo Biol 23:501–512, 2004. © 2004 Wiley-Liss, Inc.