Monitoring luteal function in the lion-tailed macaque (Macaca silenus) through urinary progesterone metabolite measurements

Estrogen and progesterone metabolites and follicle-stimulating hormone in the aged macaque female

The study presented characterizes the ovarian and pituitary function of the aged female macaque through a complete annual reproductive cycle to compare hormone dynamics during the human and nonhuman primate menopausal transition. Data collected over an entire year from aged macaque females indicated that urinary FSHbeta subunit baseline levels statistically significantly increased in females after age-related abnormal menstrual cycles occurred. These abnormal cycles were followed by anovulation and complete cessation of follicular activity. No statistically significant difference in urinary FSHbeta subunit levels was seen between females that exhibited year-round normal ovarian cycles and those that exhibited seasonal ovarian cycles followed by an interval of anovulation during the nonbreeding season. Basal urinary estrogen metabolite levels were not observed to decrease until ovarian cycles became abnormal and FSHbeta subunit levels began to rise. Early follicular phase circulating inhibin beta levels were statistically significantly reduced only when ovariectomized females were compared to the year-round normally cycling females. A statistically nonsignificant trend toward decreased inhibin secretion, however, was apparent in aged females with normal cycles, aged females with abnormal cycles, anovulatory aged females, and finally, ovariectomized females. Whereas decreased circulating levels of dehydroepiandrosterone sulfate showed a general decline over the 1-yr study period in all groups, they were lowest in the year-round normally cycling group, progressively higher in the normal-to-anovulatory group and abnormal-to-anovulatory group, and highest in the anovulatory group. Finally, the nonbreeding season was associated with the highest number of abnormal cycles, suggesting that onset of complete ovarian senescence in these study macaques was more likely to occur during that time (i.e., females were less likely to return to normal ovarian cycles the following breeding season and more likely to exhibit permanent ovarian quiescence).

Measurement of urinary and fecal steroid metabolites during the ovarian cycle in captive and wild Japanese macaques, Macaca fuscata

We measured the concentration of steroid hormones from urine, feces, and blood samples of two captive Japanese macaques, Macaca fuscata, during nonconceptive ovarian cycles to compare the patterns of the excreted steroids with those of circulating steroids. Urine and feces were analyzed for estrone conjugates (E1C) and pregnanediol-3-glucronide (PdG) using enzyme immunoassays (EIAs), while plasma was analyzed for estradiol-17beta(E2), progesterone (P), and luteinizing hormone (LH) using radioimmunoassays (RIAs). Urinary and fecal E1C and PdG levels were approximately parallel to plasma E2 and P levels, respectively. The E1C profiles of daily urinary and fecal samples revealed a midcycle peak, followed by a sustained PdG increase lasting up to two weeks from the E1C peak. A fecal E1C peak was one day later than the urinary E1C peak. One of the captive females exhibited a discrete plasma LH peak, one indicator that ovulation has occurred, on the day following the urinary E1C peak, i.e., the same day of fecal E1C peak. We measured excreted steroids in nine wild females and determined the timing of ovulation by comparing fecal steroid profiles to those obtained in captive monkeys. Data from wild females indicated that eight of nine females conceived during their first ovulatory cycle of the sampling period, whereas the remaining female failed to conceive during the sampling period even though she ovulated. In the eight females that conceived, E1C increased again following the detected or estimated E1C peak, with levels comparable to the preovulatory peak levels, and sustained elevations of PdG for over 40 days. These data illustrate that the urinary and fecal profiles of ovarian steroid excretion obtained through the application of these noninvasive techniques provide an accurate approach for monitoring conceptive and nonconceptive ovarian cycle in captive and free-living Japanese macaques.

Recent advances in noninvasive techniques to monitor hormone-behavior interactions

This paper reviews recent advances in field endocrinology, a focus as well as a method in primatology and behavioral ecology that permits the examination of social behavior and life history through hormonal investigations in natural settings. Endocrine data complements the traditional behavioral data collected by field scientists by providing quantitative measures for the examination of adaptive tradeoffs, costs of social strategies, and reproductive and social significance of mating events. Further, investigations of the physiological mechanisms of reproductive constraint provide tests of the adaptive significance of reproductive skew in cooperative and competitive breeders. Hormone data also can provide insights into the costs of competition and aggression and the role of temperament in individual reproductive success and the evolution of social systems. New, noninvasive methods for the collection of this information have augmented and expanded field endocrinology through the use of techniques that do not require potentially confounding physical or physiological manipulations. Specifically, urine and fecal samples can be collected from free-ranging animals and contain gonadal and adrenal hormones that parallel profiles of serum hormones. Sampling, preservation, extraction, and assay methods for the analysis of excreted steroids are reviewed along with the species and questions to which these methods have been applied.