Estrogen and LH dynamics during the follicular phase of the estrous cycle in the Asian elephant

Pituitary and corpus luteum hormone patterns throughout the elephant estrous cycle have been well characterized. By contrast, analysis of follicular maturation by measurement of circulating estrogens has been uninformative. This study tested the ability of a urinary estradiol‐3‐glucuronide radioimmunoassay to noninvasively assess follicular development during the nonluteal phase of the elephant estrous cycle, and to determine the relationship between estrogen production and the “double LH surge.” Daily urine and serum samples were collected throughout seven estrous cycles from three Asian elephants, and urine was collected from an additional three females, for a total of 13 cycles. Serum was analyzed for luteinizing hormone (LH), and urine was analyzed for estrogens and progestins. Elephants exhibited a typical LH pattern, with an anovulatory LH (anLH) surge occurring approximately 21 days before the ovulatory LH (ovLH) surge. The urinary estrogen pattern indicated the presence of two follicular waves during the nonluteal phase. The first wave (anovulatory) began 5 days before the anLH surge and reached a maximum concentration the day before the peak. Thereafter, urinary estrogens declined to baseline for 2 weeks before increasing again to peak concentrations on the day of the ovLH surge. Urinary progestins were baseline throughout most of the follicular phase, increasing 2–3 days before the ovLH surge and continuing into the luteal phase. These results support previous ultrasound observations that two waves of follicular growth occur during the nonluteal phase of the elephant estrous cycle. Each wave is associated with an increase in estrogen production that stimulates an LH surge. Thus, in contrast to serum analyses, urinary estrogen monitoring appears to be a reliable method for characterizing follicular activity in the elephant. Zoo Biol 22:443–454, 2003. © 2003 Wiley‐Liss, Inc.     

Immunofluorescence study of the hypothalamo-infundibular LRH tract and serum gonadotropin levels in the female squirrel monkey during the estrous cycle

Summary The study of LRH reactive neurons of the medial basal hypothalamic group was made with rabbit antisera to unconjugated synthetic LRH, in normally cycling female squirrel monkeys.The specifically immunoreactive material present along the hypothalamo-infundibular LRH tract shows significant modifications that are particularly distinct in the lateral, posterior and anterior labia of median eminence, with a maximum concentration during the early and middle follicular phases, a sudden fall to a minimum concentration during the late follicular and ovulatory phases and with a progressive increase during the luteal and early follicular phases.Serum FSH and LH levels show a progressive decrease from the luteal phase to the late follicular phase, with differential modifications suggesting that a double regulation might take place in cycling squirrel monkeys.A parallel is suggested between the specifically reactive material along the hypothalamo-infundibular tract, serum gonadotropin levels and variations in the medial basal hypothalamic and infundibular LRH concentrations during the estrous cycle in the squirrel monkey.This work was supported by the D.G.R.S.T. (contrat 76-7-1536) and U.E.R. 3 (Faculty of Medicine). We acknowledge the help of A. Pillez (C.N.R.S.) for sectioning and staining the genital tracts     

Circadian profiles of progesterone,gonadotropins, cortisol and corticotropin in cycling and postmenopausal women

Little is known about the regulation of temporal variations of progesterone over the 24-hr span in young cycling women as well as in postmenopausal women. The purpose of the present study was to investigate the relationships between diurnal variations of progesterone and diurnal variations of hormones of the gonadotropic and corticotropic axes, and to provide further information on the source of progesterone secretion under physiological conditions. Twenty-four-hour hormonal profiles were explored under well-controlled laboratory conditions in 10 healthy women (21–36 yr old) with normal ovulatory cycles during early-mid follicular and late luteal phases, and in 8 healthy postmenopausal women (48–74 yr old). In young cycling women, significant positive relationships were found between progesterone and follicle-stimulating hormone (FSH) – but not luteinizing hormone (LH) – profiles during late luteal phase. Conversely, during follicular phase, significant positive relationships were evidenced between progesterone and cortisol profiles, but not between progesterone and FSH or LH. In postmenopausal women, strong positive correlations were found between progesterone and corticotropin (ACTH) or cortisol profiles. The present results indicate that during late luteal phase, temporal progesterone profiles are associated with FSH rather than with LH profiles. They also provide evidence that adrenal cortex is a major – or possibly the only – source of progesterone production during the follicular phase of the normal ovulatory cycle, and probably the only source after menopause.     

Pathogen disgust,but not moral disgust,changes across the menstrual cycle

The Compensatory Prophylaxis Hypothesis (CPH) proposes that during periods of increased susceptibility to infections, e.g., during the luteal phase of the menstrual cycle when progesterone suppresses immune function, women should feel more disgust toward pathogen cues and behave prophylactically. We investigate differences in disgust sensitivity and contamination sensitivity during different phases of the menstrual cycle in regularly cycling, healthy 93 rural and urban Polish women using the within-subject design. Disgust sensitivity was measured during two different phases of a menstrual cycle: 1) the follicular phase (the 5th or 6th day of the cycle) and 2) the luteal phase (on the 5th day after a positive ovulatory test or on 20th day of a cycle if the result of the ovulatory test was not positive). In the luteal phase, women scored higher on the Pathogen Disgust of the Three-Domain Disgust Scale, the Contamination Obsessions and Washing Compulsions Subscale of Padua Inventory, and on ratings of photographs showing sources of potential infections than in the follicular phase. Moral Disgust of the Three-Domain Disgust Scale did not differ between cycle phases. Hence, results suggest that women feel more disgusted toward cues to pathogens during the luteal phase, when susceptibility to infection is greater. We suggest that it is necessary to incorporate ovulatory testing as well as to conduct repeated measurements of disgust sensitivity in future tests of the CPH. Moreover, we believe that understanding how the feeling of pathogen disgust varies across the menstrual cycle and in relation to progesterone levels could be useful in designing effective infectious diseases prevention strategies for women.     

Changes in plasma estradiol, progesterone and LH level in the menstrual cycle of the adult female Japanese monkey during the mating season

Adult 15 female Japanese monkeys showing regular menstrual cycles were subjected to the daily blood sampling for the measurement of estradiol (E2), progesterone (P) and biological LH in the mating season. Monkeys were maintained under controlled conditions in a standardized environment. Of the 35 cycles observed, 18 (51.4%) were estimated as anovulatory cycles and 17 (48.6%) were ovulatory cycles. The anovulatory cycles were classified into three types according to the peak level of E2 (Type I: E2 less than 50 pg/ml 3 cycles, Type II: E2 less than 170 pg/ml 7 cycles, Type III: E2 greater than 170 pg/ml 8 cycles). The ovulatory cycles were classified into two Types according to the peak level of P (Type IV: P less than 5.0 ng/ml 5 cycles, Tyep V: P greater than 5.0 ng/ml 12 cycles). The menstrual cycle was 27.5 +/- 7.8 days. The differences between mid cycle LH surge and P level in Type IV and in Type V were statistically significant. It was revealed that female Japanese monkeys kept under controlled condition in the mating season showed high incidence of various types of anovulatory cycles and that the ovulatory cycles with low P elevation in the mid luteal phase showed low LH and P secretions on the mid cycle date.     

The use of low-frequency vocalizations in African elephant(Loxodonta africana) reproductive strategies

Fertility-advertisement calls in females are predicted to occur in nonmonogamous species where males and females are widely separated in space. In African elephants, low-frequency vocalizations have thus been suggested as a reproductive strategy used by fertile females to attract mates. This study examined the use of low-frequency vocalizations with respect to different phases of the estrous cycle in African elephants by simultaneously monitoring vocalizations, behavior, and hormonal profiles. Subjects were one male and six female African elephants housed at Disney's Animal Kingdom. No acoustically distinct vocalizations were restricted to the ovulatory follicular phase. However, overall rate of low-frequency vocalization as well as the rate of one acoustically distinct vocalization changed over the estrous cycle, with highest rates of calling related to the first period of follicular growth, or anovulatory follicular phase. Elevated rates of vocalization thus were not restricted to behavioral estrus and occurred much earlier in the estrous cycle than in most species that produce fertility-advertisement calls. Both herd composition and elephant identity also affected rates of vocalization. Vocalizations therefore may not be reliable signals of actual fertility. However, the increase in vocalizations in advance of estrus may attract males to the herd prior to ovulation, facilitating both male-male competition and female choice. Once present in the herd, males may then switch strategies to use more reliable chemical and visual cues to detect ovulating females.     

Estrous state influences on investigative,aggressive, and tail flicking behavior in captive female Asian elephants

Females of species that live in matrilineal hierarchies may compete for temporally limited resources, yet maintain social harmony to facilitate cohesion. The relative degree of aggressive and nonaggressive interactions may depend on the reproductive condition of sender and receiver. Individuals can benefit by clearly signaling and detecting reproductive condition. Asian elephants (Elephas maximus) live in social matrilineal herds. Females have long estrous cycles (14–16 weeks) composed of luteal (8–12 weeks) and follicular (4–8 weeks) phases. In this study, we observed the behavior of four captive Asian elephant females during multiple estrous cycles over 2 years. We evaluated whether investigative, aggressive, and tail flicking behaviors were related to reproductive condition. Investigative trunk tip contacts showed no distinct pattern by senders, but were more prevalent toward female elephants that were in their follicular compared with their luteal phase. The genital area was the most frequently contacted region and may release reproductively related chemosignals. Aggression did not differ significantly with estrus; however, rates of aggression were elevated when senders were approaching ovulation and receivers were in the luteal phase. Females in the follicular phase may honestly advertise their condition. Contacts by conspecifics may serve to assess condition and reduce aggression. A behavior termed “tail flicking” was performed mainly during the mid‐follicular phase when estrogen and luteinizing hormone levels are known to spike. Tail flicking may disperse chemical signals in urine or mucus as well as act as a tonic signal that could provide a means of anticipating forthcoming ovulation by elephants and also for human observers and caretakers. Zoo Biol 27:167–180, 2008. © 2008 Wiley‐Liss, Inc.     

Naloxone enhances LH but not FSH release during various phases of the estrous cycle in the ewe

Suffolk x whiteface ewes were infused with 0.5 mg/kg/hr naloxone hydrochloride (NAL) for 6 hrs during the early, mid and late luteal and early follicular phases of the estrous cycle. Basal serum luteinizing hormone (LH) concentration was increased by NAL during each trial in the luteal phase and LH pulse amplitude was proportionately increased by 158%, 164% and 350% during the early luteal, mid luteal and early follicular phases, respectively. The apparent NAL induced increase (92%) in LH pulse amplitude during the late luteal phase was not significant. NAL only affected LH pulse frequency during the early follicular phase, when it was decreased. Mean serum follicle stimulating hormone (FSH) concentration was not affected by NAL. The results of this study indicate that endogenous opioid peptides (EOPs) may partially mediate the suppressive influence of estradiol-17 beta (E2) on LH pulse amplitude and also the stimulatory effect of E2 on LH pulse frequency in the early follicular phase. The data may suggest that NAL enhances the amplitude of pulses of gonadotropin releasing hormone (GnRH) by counteracting E2 inhibitory effects on LH release at the level of the pituitary. Alternately, some component of E2 feedback may be an EOP mediated component at the level of the hypothalamus.     

Relation between levels of circulating ovarian steroids and pituitary gonadotropin content during the menstrual cycle of the rhesus monkey

Anterior pituitary glands were removed from 27 intact cycling rhesus monkeys sacrificed in the early (Day 2), mid (Days 6--9) and late (Days 11--12) follicular phase, and in the early and late luteal phase (3--5 and 10--15 days after the midcycle luteinizing hormone (LH) surge). Assignment of cycle stage was confirmed by the pattern of circulating steroid and gonadotropin levels seen in the blood samples taken daily throughout the cycle. The anterior pituitary glands were weighed, stored at -30 degrees C and assayed for LH and follicle-stimulating hormone (FSH) content by specific radioimmunoassays. Serum estradiol levels and pituitary LH and FSH contents rose simultaneously during the follicular phase. After the preovulatory gonadotropin surge, pituitary LH content was low and invariant. Pituitary FSH content reached a nadir in the early luteal phase and tended to rise in the late luteal phase. Multiple correlation analyses revealed that there is a positive correlation between rising levels of estradiol in the circulation and pituitary LH (p = 0.003) and FSH (p = 0.017) content, and that there is a significant negative correlation between circulating progesterone levels and pituitary FSH content (p = 0.002). Pituitary LH content is less strongly related to circulating progesterone levels. There was no significant difference in the wet weights of the anterior pituitary glands during the five phases of the menstrual cycle studied.     

Menstrual variation in salivary testosterone among regularly cycling women.

To determine menstrual variation in salivary testosterone daily saliva samples were collected from 20 regularly cycling women. Results indicate that the menstrual profile of salivary testosterone for both ovulatory and anovulatory cycles exhibits local peaks during the follicular phase and at midcycle, as well as a luteal trough. However, the testosterone profile for anovulatory cycles exhibited a later midcycle peak than that for ovulatory cycles, as well as significantly higher average testosterone levels. These results extend the observation of a midcycle peak in serum testosterone to saliva and suggest the existence of a follicular peak in unbound testosterone coincident with the early androgen production of a cohort of developing follicles.     

Dynamics of circulating concentrations of gonadotropins and ovarian hormones throughout the menstrual cycle in the bonnet monkey: role of inhibin A in the regulation of follicle‐stimulating hormone secretion

In higher primates, increased circulating follicle‐stimulating hormone (FSH) levels seen during late menstrual cycle and during menstruation has been suggested to be necessary for initiation of follicular growth, recruitment of follicles and eventually culminating in ovulation of a single follicle. With a view to establish the dynamics of circulating FSH secretion with that of inhibin A (INH A) and progesterone (P₄) secretions during the menstrual cycle, blood was collected daily from bonnet monkeys beginning day 1 of the menstrual cycle up to 35 days. Serum INH A levels were low during early follicular phase, increased significantly coinciding with the mid cycle luteinizing hormone (LH) surge to reach maximal levels during the mid luteal phase before declining at the late luteal phase, essentially paralleling the pattern of P₄ secretion seen throughout the luteal phase. Circulating FSH levels were low during early and mid luteal phases, but progressively increased during the late luteal phase and remained high for few days after the onset of menses. In another experiment, lutectomy performed during the mid luteal phase resulted in significant decrease in INH A concentration within 2 hr (58.3±2 vs. 27.3±3 pg/mL), and a 2‐ to 3‐fold rise in circulating FSH levels by 24 hr (0.20±0.02 vs. 0.53±0.14 ng/mL) that remained high until 48 hr postlutectomy. Systemic administration of Cetrorelix (150 µg/kg body weight), a gonadotropin releasing hormone receptor antagonist, at mid luteal phase in monkeys led to suppression of serum INH A and P₄ concentrations 24 hr post treatment, but circulating FSH levels did not change. Administration of exogenous LH, but not FSH, significantly increased INH A concentration. The results taken together suggest a tight coupling between LH and INH A secretion and that INH A is largely responsible for maintenance of low FSH concentration seen during the luteal phase. Am. J. Primatol. 71:817–824, 2009. © 2009 Wiley‐Liss, Inc.     

Reproductive cycles of horses

Horses are long-day breeders. During the breeding season, cycle length is about 22 days with 5-7 days of oestrus. Gonadotroph cells are localized in the pars distalis as well the pars tuberalis of the pituitary and heterogeneity in the pattern of LH and FSH storage within the gonadotroph population is considered the basis for the differential regulation of gonadotrophin secretion throughout the reproductive cycle. No short and distinct periovulatory LH peak exists in the mare. The equine ovary has an extreme large size and weight. One to two major follicular waves develop per cycle. The preovulatory follicle reaches an average size of 40 mm. Only granulosa cells develop into luteal cells. Progesterone increases at the time of ovulation and reaches maximal concentrations on day 8. Functional luteolysis occurs around day 15 and is initiated by endometrial secretion of PGF(2α). In contrast to other species, no significant luteal oxytocin synthesis exists in the mare. During the oestrous cycle, uterus, vagina and endometrium undergo pronounced changes related to variations in the endocrine milieu. Seasonal reproductive activity is stimulated by photoperiod together with exogenous factors. The anovulatory season can be differentiated into an autumn transitional phase, a mid-anovulatory period and a spring transitional phase bringing the mare back into cyclic activity. During the mid-anovulatory period, follicular development is minimal. The beginning of the spring transitional period is characterized by the development of 1-3 anovulatory follicular waves before ovulation occurs and the most important factor for the re-initiation of ovulatory activity is the occurrence of repeated pronounced increases in circulating LH.     

Testing for Links Between Female Urine Odor and Male Sexual Behaviors in Japanese Macaques (<Emphasis Type="Italic">Macaca fuscata</Emphasis>)

Urine is involved in sexual communication in New World monkeys and lemurs, but most studies of the role of olfaction in sexual communication in Old World monkeys have focused on vaginal secretions rather than urine. We investigated whether female urine promotes male sexual behaviors (approaches and inspections of genital area) in Japanese macaques (Macaca fuscata). We used a sequential presentation paradigm in behavioral experiments, presenting unfamiliar female urine and control cotton swabs to males living in a social group with cycling females. We tested whether males (N = 3) showed more processing behaviors (licking, sniffing, tasting) toward female urine (22 stimuli per male from prefertile, fertile, and postfertile phases, based on urinary estrone and progesterone conjugate profiles) than control odor (8 stimuli per male). We then compared male sexual behaviors toward resident females pre- and post-exposure to stimuli and in relation to the females’ reproductive status (perifertile, nonfertile, and pregnancy periods, based on fecal estrone and progesterone conjugate profiles). We found that males showed significantly more processing behaviors toward urine stimuli than to controls but that male behavior did not vary across urine samples from prefertile, fertile, and postfertile phases. Exposure to unfamiliar female urine stimuli did not modulate male approaches to and inspections of resident females at any stage of the female reproductive cycle. Although our study is limited by its small sample size, the results suggest that female urine contains compounds that males detect, but we found no evidence that female urine is related to male sexual behaviors.     

Plasma insulin and glucagon concentrations and biochemical variables in regularly menstruating females with ovulatory and anovulatory menstrual cycles.

Ovarian hormones are known to affect endocrine pancreas function. However, data concerning the effects of anovulatory menstrual cycles in regularly menstruating women on endocrine pancreas and blood metabolites are lacking. We examined plasma insulin, glucagon, glucose, lactate, urea and glycerol concentrations in reproductive-age, regularly menstruating females classified as ovulating or non-ovulating on the basis of basal body temperature measurements and plasma 17beta-estradiol and progesterone determinations. All measurements were performed twice--in the follicular and again in the luteal phases of the menstrual cycle. There were no differences in plasma lactate and glycerol concentrations between the two groups of subjects. Plasma insulin concentrations tended to be lower in non-ovulating than in ovulating women. In addition, plasma glucagon did not differ in the follicular (33.2 pmol/l) or luteal phase of the menstrual cycle in females with disturbed ovarian hormone secretion (34.1 pmol/l). In contrast, plasma glucagon concentrations in the luteal phase (32.8 pmol/l) were significantly higher than in the follicular phase (24.9 pmol/l) of the menstrual cycle in ovulating women. Plasma glucose concentrations in the follicular phase of the menstrual cycle in non-ovulating women (4.1 mmol/l) were slightly but significantly lower than in their ovulating counterparts (5.3 mmol/l). Furthermore, no correlations were noted between plasma glucose and insulin-to-glucagon molar ratio in non-ovulating subjects. Plasma urea concentrations in non-ovulating women were markedly lower than in ovulating women in both follicular and luteal phases of the menstrual cycle (4.1 and 3.9 mmol/l vs. 5.3 and 5.4 mmol/l in non-ovulating and ovulating women, respectively). In ovulating women, plasma urea levels in both cycle phases were significantly correlated with plasma glucagon concentrations, but no such correlation was found in non-ovulating women. In conclusion, anovulatory menstrual cycles in premenopausal females slightly altered pancreatic hormone plasma levels but markedly impaired their action on plasma glucose and urea concentrations.     

Role of the double luteinizing hormone peak, luteinizing follicles, and the secretion of inhibin for dominant follicle selection in Asian elephants (Elephas maximus)

Elephants express two luteinizing hormone (LH) peaks timed 3 wk apart during the follicular phase. This is in marked contrast with the classic mammalian estrous cycle model with its single, ovulation-inducing LH peak. It is not clear why ovulation and a rise in progesterone only occur after the second LH peak in elephants. However, by combining ovarian ultrasound and hormone measurements in five Asian elephants (Elephas maximus), we have found a novel strategy for dominant follicle selection and luteal tissue accumulation. Two distinct waves of follicles develop during the follicular phase, each of which is terminated by an LH peak. At the first (anovulatory) LH surge, the largest follicles measure between 10 and 19.0 mm. At 7 ± 2.4 days before the second (ovulatory) LH surge, luteinization of these large follicles occurs. Simultaneously with luteinized follicle (LUF) formation, immunoreactive (ir) inhibin concentrations rise and stay elevated for 41.8 ± 5.8 days after ovulation and the subsequent rise in progesterone. We have found a significant relationship between LUF diameter and serum ir-inhibin level (r(2) = 0.82, P < 0.001). The results indicate that circulating ir-inhibin concentrations are derived from the luteinized granulosa cells of LUFs. Therefore, it appears that the development of LUFs is a precondition for inhibin secretion, which in turn impacts the selection of the ovulatory follicle. Only now, a single dominant follicle may deviate from the second follicular wave and ovulate after the second LH peak. Thus, elephants have evolved a different strategy for corpus luteum formation and selection of the ovulatory follicle as compared with other mammals.     

Menstrual cycle-related changes in plasma oxytocin are relevant to normal sexual function in healthy women

Circulating levels of the neuro-hypophysial nonapeptide oxytocin increase during sexual arousal and orgasm in both men and women. A few studies have evaluated the effect of the menstrual cycle on plasma oxytocin in normally cycling, sexually active, healthy fertile women using or not using contraceptive pills. In 20 ovulating women and 10 women taking an oral contraceptive (group 1 and group 2, respectively), sexual function, hormonal profile, and plasma oxytocin (OT) were evaluated throughout the menstrual cycle. In group 1, plasma OT was significantly lower during the luteal phase in comparison with both the follicular and ovulatory phases. Plasma oxytocin was significantly correlated with the lubrication domain of the Female Sexual Function Index (FSFI) during the luteal phase and showed a trend towards statistical significance during the follicular phase. In group 2, plasma OT did not show any significant fluctuation throughout the menstrual cycle, even though a significant correlation was evident with both the arousal and the lubrication domain of the FSFI during the assumption of the contraceptive pill. These findings suggest that plasma OT fluctuates throughout the menstrual cycle in normally cycling healthy fertile women with adequate sexual activity but not taking any oral contraceptive pill. Moreover, plasma OT levels significantly relates to the genital lubrication in both women taking and not taking oral contraceptive pill apparently confirming its role in peripheral activation of sexual function.     

Seasonal effects on the endocrine pattern of semi-captive female Asian elephants (Elephas maximus): timing of the anovulatory luteinizing hormone surge determines the length of the estrous cycle

Better breeding strategies for captive Asian elephants in range countries are needed to increase populations; this requires a thorough understanding of their reproductive physiology and factors affecting ovarian activity. Weekly blood samples were collected for 3.9 years from 22 semi-captive female Asian elephants in Thai elephant camps to characterize LH and progestin patterns throughout the estrous cycle. The duration of the estrous cycle was 14.6+/-0.2 weeks (mean+/-S.E.M.; n=71), with follicular and luteal phases of 6.1+/-0.2 and 8.5+/-0.2 weeks, respectively. Season had no significant effect on the overall length of the estrous cycle. However, follicular and luteal phase lengths varied among seasons and were negatively correlated (r=-0.658; P<0.01). During the follicular phase, the interval between the decrease in progestin concentrations to baseline and the anovulatory LH (anLH) surge varied in duration (average 25.9+/-2.0 days, range 7-41, n=23), and was longer in the rainy season (33.4+/-1.8 days, n=10) than in both the winter (22.2+/-4.5 days, n=5; P<0.05) and summer (18.9+/-2.6 days, n=8; P<0.05). By contrast, the interval between the anLH and ovulatory LH (ovLH) surge was more consistent (19.0+/-0.1 days, range 18-20, n=14). Thus, seasonal variation in estrous cycle characteristics were mediated by endocrine events during the early follicular phase, specifically related to timing of the anLH surge. Overall reproductive hormone patterns in Thai camp elephants were not markedly different from those in western zoos. However, this study was the first to more closely examine how timing of the LH surges impacted estrous cycle length in Asian elephants. These findings, and the ability to monitor reproductive hormones in range countries (and potentially in the field), should improve breeding management of captive and semi-wild elephants.     

Features of cardiovascular functioning during different phases of the menstrual cycle

The purpose of the present study was to determine whether there is a menstrual cycle effect on heart rate, blood pressure and heart rate variability. 10 healthy regularly cycling females (age 19-23 years) were studied during the follicular phase and luteal phase over two month. We found significant changes in heart rate, AMo and stress index during the menstrual cycle with a minimum in the follicular phase and maximum in the luteal phase. The HF and LF components decreased more during the luteal phase than during the follicular phase (p < 0.05), whereas a tendency for increase LF/HF was observed in the luteal phase. In the follicular phase SDNN, pNN50, Mo, MxDMn were significantly higher than in the luteal phase. Furthermore, the VIK was higher in the luteal phase compared to the follicular phase (p = 0.003). Blood pressure did not show any significant change during both these phases of the menstrual cycle. These findings indicate that sympathetic nervous activity in the luteal phase is greater than in the follicular phase, whereas parasympathetic nervous activity is predominant in the follicular phase. A difference of the balance of ovarian hormones may be responsible for these changes of autonomic functions during the menstrual cycle.     

Effect of season on hormonal profile and some biochemical parameters at different stages of estrous cycles in Baladi goats

Understanding the seasonal patterns of estrus cycle in caprine is crucial to develop the efficient breeding plans in the subtropics. Thus, the aim of the current research was to evaluate the effects of breeding season on hormonal profile and blood biochemical indices at different stages of estrus cycle in normal breeding or out-of-season breeding in goats. Forty-four Baladi goats were monitored for a period of eight months (July–February). Baladi goats exhibit a normal seasonal breeding (NS) at midsummer and continue through the autumn season (68%), with a considerable percentage of females having estrus signs during out-of-season (OS) period (32%). At the mid and late luteal phases of estrus cycles, the NS breeding group had significantly higher serum progesterone level than that reported in the OS group (p = 0.013 and 0.039, respectively). At the estrus and late luteal phases of estrus cycles, the NS breeding group had significantly higher serum β-estradiol level than that reported in the OS group (p = 0.022 and 0.001, respectively). Compared to the OS group, the NS breeding group had significantly higher serum cholesterol at the mid and late luteal phases of estrus cycle (p = 0.001 and 0.016, respectively), and higher serum glucose level in the early luteal phase of the cycle (p = 0.009). In conclusion, the NS breeding goats had superior progesterone (mid-luteal and late luteal phases) and estradiol (estrus and late luteal phases) profiles than that reported in the OS group. This may indicate specific approaches to maintain the breeding efficiency of goats during the out-of-season period.     

Relationship between ovarian cycle phase and sexual behavior in female Japanese macaques (Macaca fuscata)

We conducted behavioral observations simultaneously with fecal sample collection on eight nonlactating females 2-3 times per week, October 1997-March 1998, to examine the relationship between ovarian hormones and the sexual behavior of female Japanese macaques (Macaca fuscata) during the mating season. We analyzed samples by enzyme immunoassay for fecal hormone levels. Hormone profiles of estrone-glucuronide (E1) and pregnanediol-glucuronide (PdG) were used to separate ovarian cycles into three phases (follicular, periovulatory, and luteal). Hormonal profiles indicate average cycle lengths of 27.6 +/- 4.2 days (+/- SD; n = 26). Average lengths of the luteal and follicular phases were 12.3 +/- 3.8 days (+/- SD) and 8.3 +/- 3.4 days (+/- SD), respectively. We observed female Japanese macaques engaging in sexual activity throughout the ovarian cycle, with the highest rates occurring during the follicular and periovulatory phases as compared to the luteal phase. The attractivity of female Japanese macaques increased significantly during the follicular and periovulatory phases of the ovarian cycle, when E1 levels are peaking and PdG levels drop to baseline. In addition, females displayed a significant increase in proceptive behavior during the follicular and periovulatory phases. Grooming bouts, as well as proximity between female and male macaques, also increased significantly during the follicular and periovulatory phases. We conclude that fluctuating levels of ovarian hormones in different phases of the cycle are significantly associated with variable rates of copulatory and pericopulatory behaviors in these Japanese macaque females.