Periovulatory time courses of serum LH in the Japanese monkey (Macaca fuscata)

Serum LH, E2-17 beta and progesterone concentration were measured in 16 cycles of 15 female Japanese monkeys. Three of the 16 cycles were ascertained to be anovulatory. Ten of the 13 ovulatory cycles showed LH peaks varying from 25 to 280 ng/ml. However, in remaining 3 cycles, LH peak could not be determined, probably because of a lag of blood-sampling schedule. E2-17 beta peaks were detected 0-30 hrs before LH peak in 8 cycles, but 13 or 20 hrs after LH peak in 2 cycles. Time-intervals from LH peak to ovulation ranged 0-47 hrs 30 min. No correlation was detected between concentrations of LH and progesterone in the luteal phase.     

Lactation‐associated infertility in Japanese monkeys (Macaca fuscata) during the breeding season

To investigate the endocrine factors in Japanese monkeys (Macaca fuscata) responsible for the suppression of the estrous cycle during the first reproductive season after delivery (150–360 days postpartum), peripheral blood was taken to measure plasma concentrations of follicle stimulating hormone (FSH), luteinizing hormone (LH), progesterone, estradiol‐17β, immunoreactive (ir)‐inhibin, and cortisol. The results demonstrated that during the breeding season of lactating Japanese monkeys, circulating concentrations of FSH (1.7–2.7 ng/ml), LH (308.5–461.0 pg/ml), estradiol‐17β (<62.6 pg/ml), and progesterone (145.0–453.0 pg/ml) remained low and were similar to the nadir levels observed during both the normal menstrual cycles and the nonbreeding season. Concentrations of ir‐inhibin, which is secreted from both follicles and corpus luteum in female Japanese monkeys, were also low (300.5–585.0 pg/ml). This strongly suggests that no follicular development occurs during lactation. Serum concentrations of cortisol (261.0–519 ng/ml) were higher during lactation than during the nonbreeding season. Since babies were often seen suckling their mothers during the study, the results indicate that the increased cortisol levels were associated with suckling‐induced secretion of corticotrophin‐releasing hormone (CRH) and adrenocorticotropic hormone (ACTH). The results of this study indicate that a long period of postpartum infertility in lactating Japanese monkeys, with apparent inhibition of follicle growth and anovulation, is due to weak gonadotropin stimulation, which may occur as the result of a suckling stimulus. Zoo Biol 22:65–76, 2003. © 2003 Wiley‐Liss, Inc.     

Contraceptive potential of an antiprogestin ZK 98.734: reversal of ZK 98.734--induced blockade of folliculogenesis with FSH and LH and their differential effects in bonnet monkeys.

Studies were undertaken in adult bonnet monkeys to investigate whether treatment with an antiprogestin ZK 98.734 at weekly intervals, starting from day one of menstrual cycle, could arrest ovulation and also to determine if ZK 98.734 induced blockade of ovulation could be reversed with gonadotropins. Adult animals have ovulatory menstrual cycles of normal duration were treated at weekly intervals with ZK 98.734 (25 mg/dose, sc, oil base) for 10 consecutive weeks and its effects on serum levels of estradiol, bioactive LH and progesterone, and endometrial histology were investigated. Following treatment with the antiprogestin they were treated with hMG or hFSH alone. Ovulation was blocked during treatment period in all the animals (n = 14). Typical follicular phase rise in estradiol levels was inhibited, mid cycle surge in the levels of bioactive LH was abolished and serum progesterone levels remained below 1 ng/ml throughout the treatment period. However, prolonged treatment had no significant effect on the basal levels of estradiol which were around 50 pg/ml. ZK 98.734 also had no significant effect on cortisol levels. In animals (n = 4) followed for recovery after the last dose, the treatment cycle length was increased to 117.8 + 6.8 days. In three animals the treatment cycles were anovulatory, whereas in one delayed ovulation with luteal insufficiency was observed. The endometrium had become atrophic. Treatment with hMG (Pergonal: 35 I.U. hLH and 35 I.U. hFSH) or hFSH (Metrodin, 35 I.U.) for 7 consecutive days initiated folliculogenesis and the animals ovulated either spontaneously or after a single im injection of hCG (100 I.U.) on day 8 in ZK 98.734 treated animals.(ABSTRACT TRUNCATED AT 250 WORDS)     

Periovulatory time courses of plasma estradiol and progesterone in the Japanese monkey (Macaca fuscata)

Periovulatory time courses of plasma estradiol and progesterone were determined in 21 menstrual cycles of 20 Japanese monkeys. Both steroids were measured by radioimmunoassay. Ovulation was detected by serial laparoscopic observations of the ovaries. Three of the 21 cycles were anovulatory cycles. In the remaining 18 ovulatory cycles, a preovulatory estradiol peak occurred on day 12.2±1.4 (range 10–15) of the menstrual cycle. The estradiol concentration at the peak was 431±199 (range 210–930) pg/ml. The time interval between the estradiol peak and ovulation was within 48 hr; the shortest interval was 10–13 hr and the longest 32–48 hr. Although the progesterone levels began to increase slightly (0.6–1.4 ng/ml) before ovulation, they did not show a continuous increase but decreased once before ovulation. The increase in progesterone with development of the corpus luteum after ovulation was very gradual during the first 2 days after ovulation. Subsequently, in 13 of 18 ovulatory cycles the progesterone levels rose rapidly and reached a maximum, 4.0±1.2 (range 2.3–5.7) ng/ml, 4–8 days after ovulation. In 5 of the 18 cycles, the progesterone levels did not rise at all or did not exceed 2.0 ng/ml even if they showed more or less an increase. In the 5 cycles, the length of the luteal phase was 8.2±1.6 (range 6–10) days, which was significantly shorter than that of the former 13 cycles with 14.0±1.1 (range 13–16) days.     

Seasonal effects on ovarian folliculogenesis in rhesus monkeys

Reproductive performance is reportedly reduced in some rhesus monkeys during the summer months, even when environmental conditions are controlled. The mechanism(s) underlying this phenomenon remain unknown. We noted that the pattern of folliculogenesis appeared to be altered in rhesus monkeys that continued to exhibit ovulatory menstrual cycles during the "nonbreeding" season. This study was designed to investigate the effect of season on development of the dominant follicle (DF) and upon levels of serum gonadotropins and sex steroids in animals maintained in a controlled environment. Forty-four menstrual cycles were evaluated from October, 1982 to October, 1983. Animals were housed individually in controlled light (12L:12D) and temperature (22-25 degrees C). A DF was identified by laparoscopy on Day 6 of the cycle in only 45% of cycles during the months of May through September, compared with 87.5% the remainder of the year. No effect of season was detected on either the length of the menstrual cycle or luteal phase, mean follicular diameter, or the percentage of ovulatory cycles. During the follicular phase, amounts of follicle-stimulating hormone (FSH) in peripheral sera were depressed, whereas those of luteinizing hormone (LH) were consistently elevated. Amounts of circulating estradiol were similar between groups. However, serum concentrations of progesterone were markedly reduced in the summer. Development of the DF appeared to be delayed in the early follicular phase during the summer months in those rhesus monkeys that had ovulatory menstrual cycles. This delay was accompanied by an alteration in the FSH to LH ratio. Although most cycles were ovulatory, altered follicular development resulted in deficient luteal function.     

Seasonal modulation of luteinizing-hormone secretion in female rhesus monkeys

The seasonal restriction of ovulations in rhesus monkeys is thought to be due to enhanced estradiol (E2)-negative feedback suppression of luteinizing hormone (LH) during the spring and summer anovulatory months. This hypothesis was examined in seven ovariectomized monkeys housed in an outdoor environment and treated with various doses of E2 in a counterbalanced design during both the anovulatory season (May-Jul) and the breeding season (Sep-Nov). Subcutaneous implants of E2 produced levels that mimicked late follicular (LF-100 pg/ml) or periovulatory concentrations (PO-190 pg/ml). Analyses of twice weekly serum samples revealed that during the period of no E2 treatment (NT), basal levels of bioactive LH were significantly lower in the summer than the fall. Although treatment with both doses of E2 lowered basal LH levels during both seasons, the decrease in LH was significantly greater during the summer. Samples collected at 15-min intervals for 2 h revealed that during NT, LH pulses were significantly slower during the summer than in the fall, whereas pulse amplitude did not differ between seasons. Treatment with both doses of E2 either abolished or significantly reduced both LH pulse amplitude and frequency in the summer. In contrast, LH pulses during the fall were not affected by E2 treatment. Response to treatment with LH-releasing hormone (5 micrograms/kg i.v.) revealed that release was significantly reduced during E2 treatment in the summer. These data indicate that seasonal changes in the environment influence both nongonadal control and E2-negative feedback inhibition of LH secretion. The reduced ability of E2 to maximally suppress LH release in the fall can thus account for the seasonally delimited pattern of ovulations observed in rhesus monkeys.     

Menstrual cycle characteristics of seasonally breeding rhesus monkeys

Rhesus monkeys in seminatural environments exhibit a distinct seasonal mating cycle with conceptions restricted to the fall and winter months. In the present study, the characteristics of menstrual cycles were examined during a 1-year period in twelve rhesus monkeys in whom pregnancy was prevented. Menses occurred throughout the year, but ovulations were observed only in the fall and winter months. Menses in the spring and summer months occurred irregularly and were associated exclusively with anovulatory cycles. The total number of ovulations exhibited by these females during the breeding season ranged from two to six and was positively related to body weight, mean luteal phase progesterone (P) levels of normal cycles and social dominance rank. Ovulations with a short luteal phase were exhibited by four females (seven cycles), with the likelihood of occurrence increasing as the breeding season progressed. The incidence of abnormal cycles was predicted from the linear combination of parity, body weight and luteal phase P of normal ovulatory cycles. These results suggest that during the seasonally delimited period of ovulation, females exhibit a range in the quality and quantity of ovulations which may be predicted by certain idiosyncratic physical and behavioral traits.     

Suppressed copulatory behavior and ovarian function in lactating Japanese monkeys (Macaca fuscata fuscata) during the mating season

The influence of lactation on copulatory behaviors and ovarian functions was studied in Japanese monkeys (Macaca fuscata fuscata) during the mating season. Three lactating females were housed in an outdoor group cage with their infants, and three nonlactating females were housed in an adjacent outdoor cage. They were mated by introduction of one of four rotationally chosen males into the females' cage, for two hours three times a week; the occurrence of ejaculatory copulations was recorded. Blood samples were collected on each observation day, and plasma levels of estradiol, progesterone, and luteinizing hormone (LH) were measured by specific radioimmunoassays. In nonlactating females, plasma estradiol increased during the transition into the mating season, and rose to levels over 90 pg/ml for the first time on about 50 days before the first ovulation. Shortly after plasma estradiol exceeded 90 pg/ml in the nonlactating females, the onset of ejaculatory copulations occurred. They received ejaculations continuously up to the early ovarian luteal phase. On the other hand, in lactating females, there were lower levels of plasma estradiol (below 90 pg/ml) during the transition into the mating season, and they received no ejaculation during that period. Two of the three lactating females ovulated only once, and they received ejaculations only during the periovulatory period, coinciding with the rise of their plasma estradiol levels over 90 pg/ml. The remaining lactating female remained anovulatory and received no ejaculation throughout the entire mating season. These results have demonstrated that the low sexual activity of lactating females is clearly correlated with low levels of plasma estradiol due to suppressed ovarian function.     

Preliminary observations on the collection of baboon oviducal fluid

Five sexually mature and regularly ovulating baboons (Papio cyanocephalus) were subjected to bilateral oviducal cannulation. Prior to failure of the primary cannulation, peri-ovulatory fluids were collected during three menstrual cycles from one animal, during two cycles from a second animal, and during a single cycle from each of two additional animals. These four animals were subsequently recannulated and oviducal fluids obtained during six additional cycles, but tubal fluid collection after the second procedure was generally less satisfactory than following the initial manipulation. Two attempted cannulations in the fifth animal did not result in oviducal fluid collection. Of the 13 menstrual cycles during which tubal fluid was collected, four were apparently anovulatory. Collections from two of these as well as from three ovulatory cycles were characterized by erratic flow and mucous-blood contamination. Tubal fluids were collected without apparent technical interference or serum contamination from six ovulatory and two anovulatory cycles. Maximum volumes (1.77±.34 ml/oviduct/24 hours) of tubal fluids were collected during the 48 hours following the midcycle LH peak. Thereafter, the rate of oviducal fluid collection declined rapidly.     

Confirmation of ovulation and characterization of luteinizing hormone and progesterone secretory patterns in cycling,isosexually housed Bolivian squirrel monkeys (Saimiri boliviensis boliviensis)

In the female Bolivian squirrel monkey a much greater elevation of serum estradiol (E₂) was measured after mating than that observed in similary cycling monkeys that did not mate. This raised the possibility that cycling squirrel monkeys may not ovulate during nonmated cycles To test this hypothesis, we performed laparoscopies on nine isosexually housed, cycling monkeys to observe the ovaries after the luteinizing hormone (LH) surge, which was measured by mouse interstitial cell bioassay using LER 1909-2 as the standard. Single ovulatory stigmas were identified as well demarcated, red, punctate depressions at the center of dome-shaped elevations on the ovarian surface in eight monkeys, when laparoscopically examined 9-56 hr after the LH peak. One monkey examined laparoscopically prior to the LH surge had a large translucent cystic follicle, confirming the morphology of the mature prevulatory follicle. Mean progesterone (P) concentrations fell to a nadir 1 day prior to the LH surge and then began to rise on the LH surge. Peak P levels were found 2 days after the LH surge. In the ovulating animals in which periovulatory E₂ levels were measured, no value was greater than 800 pg/ml, indicating that the presence of follicular rupture was not sufficient to account for the elevated E₂ levels observed after mating. These data confirm ovulation and follicular rupture in the absence of mating and delineate the relationship between periovulatory LH, P, and E₂ secretory patterns in cycling squirrel monkeys.     

Failure of daily injections of ketamine HCL to adversely alter menstrual cycle length, blood estrogen, and progesterone levels in the rhesus monkey.

Failure of daily injections of ketamine hydrogen chloride (HCL) to adversely alter menstrual cycle length, blood estorgen, and progesterone levels in the rhesus monkey is reported. The study was carried out with 30 adult female monkeys to determine the effects of daily administration of 8-10 mg ketamine HCL/kg. In physically restrained control monkeys there were 14 of 25 ovulatory cycles and inketamine-treated monkeys there were 28 of 32 ovulatory cycles. Menstrual cycle length was the same in both groups. The levels and time course of estrogen and progesterone levels were the same in the ovulatory cycles of both groups. In 30% of the control cycles and in 25% of the ketamine-treated there were luteal phases in which the preovulatory estrogen levels were normal and in which the luteal-phase progesterone levels were low and variable 6-8 days after the preovulatory surge. It is concluded that the daily use of ketamine HCL does not markedly alter menstrual cycle length, or serum estrogen or progesterone levels throughout the menstrual cycle. The incidence of anovulatory cycles and premature menstrual induction was reduced probably by reducing the stress of restraining the monkey for the purpose of taking a blood sample.     

Serum levels of gonadotropins and gonadal steroids,including testosterone,during the menstrual cycle of the chimpanzee (Pan troglodytes)

The objective of this study was to expand the data on menstrual cycle serum hormone patterns in female common chimpanzees, both in terms of the number of cycles analyzed and by the addition of data on testosterone levels. Samples were obtained from 11 unanesthetized animals trained for conscious blood withdrawal. LH, FSH, 17β-estradiol (E₂), progesterone (P), and testosterone (T) were measured by radioimmunoassay, genital swelling was recorded, and menstrual blood was noted. Concurrent midcycle elevations in LH and FSH and luteal phase elevations in progesterone suggested that the cycles were ovulatory. Detumescence of genital swelling occurred about 3 days after the midcycle LH peak, 1 day after the luteal phase nadir in E₂, and 1 day after P levels exceeded 5 ng/ml. These relationships provide further support for the use of genital swelling in monitoring progress of the menstrual cycle. The hormone patterns in the chimpanzees closely resembled those of the human females, but E₂ and T levels were higher. The levels of E₂ and T were higher and the midcycle elevation in T was broader in the chimpanzee than in gorillas and orangutans. This is of interest because E₂ and T are implicated in the regulation of mating, and chimpanzees mate over a greater portion of the cycle than the other apes. These data indicate the need for further study of hormonal contributions to the different patterns of mating in the great apes. They also support the use of the female common chimpanzee as a model for the human female in endocrine studies of the menstrual cycle.     

Successful artificial insemination for indoor breeding in the Japanese monkey (Macaca fuscata) and the cynomolgus monkey (Macaca fascicularis)

Methods of artificial insemination (AI) for indoor breeding in the Japanese monkey and the Cynomolgus monkey were investigated. For the Japanese monkey AI was carried out in six females during the winter mating season and in six females during the summer non-mating season. During the mating season, semen was inseminated near ovulation time in natural menstrual cycles. In the mating season study, three females inseminated at the uterine cavity became pregnant. Three inseminated at the cervical canal failed to become pregnant. For the non-mating season study, ovulation was induced artificially by PMSG and hCG and AI was carried out near the induced ovulation time. In the non-mating season, no animals became pregnant. Of four Cynomolgus monkeys used, pregnancy occurred in two animals inseminated near ovulation time in natural menstrual cycles. AI occurred at the uterine cavity in one and cervical canal in the other. In both species ovulation was verified by laparoscopy. Semen was collected by penile electro-stimulation then diluted to 2.5 to 5.0×10⁷/ml with Whitten's medium. Diluted semen of 0.2l was inseminated at the uterine cavity or cervical canal. Our results indicate the usefulness of vaginal AI as a method of artificial indoor breeding.     

Post partum patterns of circulating FSH, LH, prolactin, estradiol, and progesterone in nonsuckling cynomolgus monkeys.

Circulating levels of FSH, LH, prolactin (Prl), estradiol (E), and progesterone (P) were determined by RIA in four intact and four monkeys luteectomized (CLX) at parturition in order to a) characterize the patterns of these hormones during the puerperium, and b) examine a possible inhibitory role of the "rejuvenated" corpus luteum (CL) on the resumption of follicle growth post partum. In both groups during the first four weeks, FSH and LH were at tonic levels typical of ovulatory cycles. Recurrent puerperal "surges" of FSH, but not LH, unaccompanied by increments in serum E, were observed in both intact and CLX monkeys. No consistent pattern of serum Prl was apparent. CLX was followed by a prompt fall in serum P levels, which were elevated above typical follicular phase levels into the second week post partum in intact monkeys. Menstrual cycles resumed 2-4 months after delivery. Hormonal patterns during the first menstrual cycle post partum were indistinguishable from those observed in pregravidic ovulatory cycles. The findings indicate that in nonsuckling cynomolgus monkeys a) although it secretes progesterone, the puerperal CL does not inhibit the resumption of the ovarian cycle post partum, b) the puerperal ovary is not absolutely refractory to gonadotropins, since initial trials with Pergonal + hCG stimulated ovarian function, and c) ovarian activity during the puerperium may be limited by factors other than the tonic supply of gonadotropins.     

Effects of an antiprogestin onapristone on the endometrium of bonnet monkeys: morphometric and ultrastructural studies

Our previous studies demonstrated the ability of low doses of antiprogestin ZK 98.299 (onapristone) to inhibit fertility in bonnet monkeys. In the present study cumulative effects of low doses of ZK 98.299 on the endometrial cytoarchitecture of bonnet monkeys were analyzed. Treatment with either the vehicle (n = 3) or onapristone at 2.5 mg (n = 4) or 5.0 mg (n = 3) was initiated on Day 5 of the first menstrual cycle and thereafter repeated every third day for four to seven consecutive cycles. The last treatment cycles were anovulatory in two animals treated with 2.5 mg and all animals treated with 5.0 mg. Endometrial biopsies were collected on Day 8 after the midcycle estradiol peak in ovulatory menstrual cycles and on Day 20 in anovulatory menstrual cycles during the last treatment cycle. Ultrathin sections of the fixed endometrium were stained with toluidine blue for morphometric analysis and uranyl acetate and lead citrate for ultrastructural analysis. The ZK 98.299-treated animals showed a dose-dependent endometrial atrophy as evident by a decrease in the height and diameter of the glands and early signs of compaction in the stroma. Ultrastructural analysis also revealed dose-dependent degenerative changes in the subcellular organelles such as the nucleus, mitochondria, endoplasmic reticulum, lysosomes, and Golgi apparatus. This suggests that long-term treatment with low doses of ZK 98.299 leads to the suppression of estrogen-dependent endometrial proliferation. However, this blockade operates independent of estradiol receptor (ER) and progesterone receptor (PR) concentrations as the expressions of these steroid receptors did not show any significant changes even after prolonged treatment. The study demonstrated an antiestrogenic effect of ZK 98.299 on endometrium after prolonged treatment in bonnet monkeys.     

Menstrual cycle and some other related aspects of Japanese monkeys (Macaca fuscata)

The menstrual cycle and some other related aspects of Japanese monkeys (Macaca fuscata) were dealt with in this paper. Almost all the monkeys had regular menstrual cycles only in the mating season, and had no menstrual cycles, or only irregular ones, in the non-mating season. The average length of the menstrual cycle in the mating season was 26.3 ±5.4 days. Many monkeys had a tendency to have their own individual and relatively regular cycles. Ninety out of 108 monkeys kept in the air-conditioned quarters for five years showed “periodical changes” essentially coincident with the changes of outdoor season, and this fact suggests that the rhythm of the seasonal change of Japanese monkeys remains for a relatively long period even if the monkeys are kept in air-conditioned quarters where room temperature and lighting are kept constant throughout the year. Vaginal smear, cervical mucus, sexual skin, etc. were observed in relation to ovulation. These characters showed cyclic changes with menstrual cycles in about half of all cases observed, but ovulation occurred even in the cases in which no cyclic change was observed. Therefore, it was not necessarily easy to estimate the ovulation by observing these characters.     

Behavioral indices of estrus in a group of captive African elephants (Loxodonta africana)

This study investigated behavioral signals of estrus by systematically monitoring the interactions of one male with four female African elephants housed in a naturalistic outdoor enclosure at Disney's Animal Kingdom over a period of 11 months. We measured changes in five spatial behaviors and 22 tactile‐contact behaviors, as well as changes in serum progestagen and LH concentrations, across three ovarian cycles for each female. Two females did not cycle during the study. Three different phases of the ovarian cycle were identified: mid luteal, anovulatory follicular, ovulatory follicular. The male followed more and carried out more genital inspections, flehmen, and trunk‐to‐mouth behaviors toward cycling females during their ovulatory phase. Genital inspections by the male peaked above baseline levels on the day of an LH surge, and up to 9 days before, in both cycling females and, thus, might be a useful behavioral index of estrus. The male also carried out more genital inspections, flehmen, and trunk touches to the back leg toward ovulatory cycling than noncycling females. Overall, our results indicated that: 1) a single subadult African elephant male could discriminate two females in the ovulatory phase of their cycle (i.e., during the 3 weeks preceding ovulation) from the mid luteal phase; 2) the male also discriminated two cycling females in the ovulatory and anovulatory follicular phases from two noncycling females; 3) two females in the ovulatory phase of the cycle displayed a greater variety of tactile‐contact behavior toward the male compared to the other cycle phases. Zoo Biol 0:1–19, 2005. © 2005 Wiley‐Liss, Inc.     

Reproductive Behavior in the Rhesus Monkey: Social and Endocrine Variables

SYNOPSIS. Social groups of rhesus monkeys (Macaca mulatto) livingin outdoor environments exhibit a distinct seasonal mating patternand female rhesus are observed to be sexually receptive fordiscrete periods averaging about 9 days duration. In the laboratoryenvironment mating occurs throughout the year and, in the pairtest, female rhesus are observedto be sexually receptive throughall phases of a menstrual cycle, with a periovulatory peak incopulatorybehavior. The apparent conflict between results from field andlaboratory studies has been difficult to resolve because ofmethodological limitations inherent in each study environment.Studies conducted on social groups of rhesus monkeys housedin outdoor compounds, an environment in which the species typicalseasonal mating pattern is preserved and which allowsfor concomitantmeasurement of behavioral and hormonal variables, provided informationabout the covariance between female sexual behavior and ovariancycles. Female copulations were observed only in associationwith ovulatory cycles, and were limited to the follicular andperi-ovulatory phases of such cycles, demonstrating that copulatorybehavior in female rhesus monkeys is strongly influenced bycyclic hormonal variables. The studies also revealed that femalestend to conceive on the first ovulatory cycle of the season,that there was no synchrony of cycles among the females, andthat the best predictor of the timing of ovulation in a particularfemale is reproductive outcome in the previous year.     

Age-dependent changes in fecal 17β-estradiol and progesterone concentrations in female spider monkeys (Ateles geoffroyi)

The objective of this study was to investigate whether sex steroids decreased with age in female black-handed spider monkeys (Ateles geoffroyi). Fecal concentrations of 17β-estradiol and progesterone (five samples/wk) and the number of ovulatory and anovulatory cycles were compared between adult (n = 3) and aged females (n = 2). All animals (regardless of age) had higher 17β-estradiol concentrations during the fertile than the nonfertile phases. However, during the fertile phase, concentrations of this hormone were significantly higher in adult females. Conversely, progesterone concentrations varied normally throughout the menstrual cycle in both adult and aged animals, with no significant difference between age classes. Similarly, there was no significant effect of age on the number of ovulatory and anovulatory cycles. In conclusion, we inferred that the aged female spider monkeys did not reach menopause, instead they remained in a perimenopausal period characterized by changes in fecal concentrations of ovarian steroids and hypothalamus-hypophysis-ovary axis activity, as well as irregular menstrual flows, for prolonged intervals.     

Menstrual irregularities in adolescents: hormonal pattern and ovarian morphology

The endocrine pattern and ovarian characteristics of 110 healthy adolescents with menstrual irregularities were investigated during the early follicular and premenstrual phases and were compared to those of 14 adolescents with regular menstrual cycles and 20 adults. Over a period of six gynecological years a low ovulation rate (49%) was found in the group of subjects with irregular cycles and regular ovulation was noted in only a few subjects. Slight differences in endocrine pattern and ovarian morphology were observed between the group of adolescents with regular cycles and the group of adults. In contrast, adolescents with irregular menses had higher mean values of luteinizing hormone (LH), testosterone (T), and androstenedione (A) in comparison with the other two groups both in follicular and premenstrual phases. Nearly 35% of the subjects with irregular cycles had levels of T, A and LH which were higher than the upper limit of the adult normal range. Lower progesterone (P), 17P and oestradiol values were observed in the premenstrual phase. Within the group of subjects with irregular menses, LH levels were higher in anovulatory than in ovulatory cycles, in both phases of the cycle, while T and A levels were higher and prolactin levels were lower in the premenstrual phase of anovulatory cycles. Unlike irregular anovulatory cycles, irregular ovulatory cycles showed a hormonal pattern similar to that found in the adult group. By ultrasound evaluation, a high percentage of subjects with irregular menses had multicystic ovaries (57.9%) and the mean (+/- SEM) ovarian volume was higher (10.6 +/- 0.5 cm3) than that found in adolescents with regular menses (6.7 +/- 0.8 cm3) and in the adult group (7.7 +/- 0.3 cm3). With the increase in frequency and continuity of ovulation an improvement in the direction of adult volume and ovarian structure was observed. Besides the endocrine similarity the data emphasize the striking similarity, already documented by histological studies, between pubertal ovaries and those seen in micropolycystic ovary syndrome. These endocrine and ovarian characteristics are typical of a large number of adolescents with irregular menstrual cycles: these features may be representative of a developmental step toward adult normality, although the possibility of a pathological evolution for some subjects cannot be excluded.