Susan E. Shideler

Estrogen and Progesterone Metabolites and Follicle-Stimulating Hormone in the Aged Macaque Female

Abstract 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 FSHβ 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 FSHβ 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 FSHβ subunit levels began to rise. Early follicular phase circulating inhibin β 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).

Use of Fecal Steroid Metabolites to Estimate the Pregnancy Rate of a Free-Ranging Herd of Tule Elk

The ability to measure reproductive hormones in urine and feces permits physiologic evaluations of free-ranging animal populations. The data from previous reports indicate specific events such as gonadal recrudescence, ovulation, conception, pregnancy, and lactation can be detected and defined by fecal hormone analysis in a wide range of animals. The present study was undertaken to determine if combined data from a ongitudinal and cross-sectional hormonal study of free-ranging cow tule elk (Cervus elaphus nannodes) and simultaneously collected observational data would permit an accurate estimation of the pregnancy rate of the population, Ovarian and placental function were monitored in 34 radiocollared cow tule elk from the onset of ovarian recrudescence in the summer of 1996, through the calving season in the spring of 1997. Estrogen and progesterone metabolites were measured by enzyme immunoassay (EIA) in fecal samples collected from both radiocollared and uncollared cows. The radiocollared cows were located and identified for individualized observations of fecal deposition and later confirmation of pregnancy by observation of nursing. Hormonal concentrations from the samples collected from the radiocollared cows in which pregnancy and outcome were known were used to set criteria for designation of a cow as pregnant in the cross-sectional samples collected from a population of approximately 208 uncollared cows. Progesterone metabolite (PdG) concentrations were 100% reliable at predicting pregnancy within the first trimester of gestation through parturition, while estrogen metabolite (E 1 C) concentrations were not a reliable indicator until the last trimester of gestation. A progesterone metabolite concentration > 1.01 ug/g dry mass feces (dmf) after the breeding season was set as confirmation of pregnancy status in fecal samples collected from uncollared cows. Analysis of hormonal concentrations after the 1997 calving season in conjunction with observations of nursing permitted pregnancy detectio estimates via the calving rate of the collared cows for the 1996-97 breeding and calving season. These same parameters were estimated and evaluated in the uncollared cows. Our results provide strong evidence that the measure of fecundity in free-ranging animals can be obtained through fecal steroid analyses, and that this measure is an accurate predictor of fertility.

Reproductive events of wild cotton-top tamarins (Saguinus oedipus) in Colombia

Reproductive patterns of wild cotton‐top tamarin (Saguinus oedipus) females located in La Reserva Forestal Protectora Serranía de Coraza‐Montes de María in Colosó, Colombia, were examined using long‐term behavioral observations and fecal steroid analysis. Using an enzyme immunoassay, we analyzed fecal samples for E1C and PdG. Comparisons of reproductive cycles of a reproductively active female and her daughters were made. An inhibition of ovarian cycles has been observed in daughters living in their families. However, daughters also exhibited normal ovarian cycling that subsequently resulted in pregnancy. Factors influencing the fertility are discussed as they relate to the reproductive strategies of wild cotton‐top tamarin females. Am. J. Primatol. 43:329–337, 1997.

A prototype for ovulation detection: Pros and cons

A noninstrumented enzyme immunoassay for urinary estrone conjugates was adapted from an instrumented microtiter plate enzyme immunoassay assay. The end point of the assay was a color change from green to clear, which was visible to the unaided eye. The visible color change was adjusted to allow 80 ng/ml estrone conjugates (on the basis of a sample size of 6.5 microliters urine) to be distinguished from an infinite dilution without instrumentation. The evaluation of human urine collected from ovulatory ovarian cycles demonstrated that early follicular phase concentrations (35.9 +/- 6.8 to 79.4 +/- 14.7 ng/ml, n = 10) produced a dark-green color, whereas late follicular phase concentrations (162.9 +/- 20.1 ng/ml, n = 10) produced no color. Daily urine samples throughout 10 ovulatory ovarian cycles produced parallel profiles when compared to measurements of estradiol in paired blood samples. Complete analysis of the data indicated that ovarian follicular dynamics can be accurately monitored through the noninstrumented analysis of daily estrone conjugates in urine samples.

Application of an enzyme immunoassay for urinary follicle‐stimulating hormone to describe the effects of an acute stressor at different stages of the menstrual cycle in female laboratory macaques

An enzyme‐linked immunosorbent assay (ELISA) for human urinary beta follicle‐stimulating hormone (FSH) subunit was validated for use in the laboratory macaque (Macaca mulatta and Macaca fasicularis). This ELISA is based on the dissociation of the FSH heterodimer in urine and the subsequent measurement of the beta subunit as a representation of total urinary FSH. This assay was then used to describe the gonadotropin escape following ovarian senescence in post‐menopausal macaques. In addition, the assay was used to observe the impact of an acute stressor on the pituitary‐gonadal axis and how the impact of this stressor varies when experienced at different stages of the menstrual cycle. The study design involved the measurement of ovarian steroids and FSH in urine collected daily during a period of time when animals experienced a well‐defined event on two occasions consisting of capture, restraint, and anesthesia. This unique study design was made possible by the ability to monitor both ovarian and pituitary function in the absence of confounding daily captures and restraint for blood collection. There was a high correlation between urinary FSH measured in macaques with the beta FSH subunit ELISA and serum FSH measured in paired blood samples by radioimmunoassay (n=39, r2=0.878, P<0.001) and the composite urinary FSH profile obtained from normal, pre‐menopausal macaques exhibited the expected dynamics with a transient rise of FSH during the luteal‐follicular transition as well as an acute rise of FSH at mid‐cycle. This pattern was lost in castrate and post‐menopausal monkeys in which FSH levels were significantly increased (P<0.0001) above those of intact males and young females, respectively. In the stress study, we found that stressors occurring during the luteal‐follicular transition not only resulted in acute perturbations of FSH but also led to abnormalities in the subsequent menstrual cycle in 50% of the cases. Am. J. Primatol. 48:135–151, 1999.

Non-Instrumented Immunoassay Field Tests for Pregnancy Detection in Free-Roaming Feral Horses

We evaluated 2 rapid non-instrumented field tests for pregnancy on feral horses (Equus caballus) because previous techniques required sophisticated and expensive instrumentation that limited their usefulness to field researchers. The measurement of urinary estrone conjugates (E,C) by an enzyme immunoassay and based on observable color changes was 100% accurate when compared with instrumented spectrophotometrically measured tests for E 1 C. A non-instrumented «dipstick» enzyme immunoassay for equine chorionic gonadotropin-like (eCG) molecules was 83% accurate in diagnosing mare pregnancies when compared with the results of the instrumented test for E 1 C

Sexual behavior and urinary ovarian hormone concentrations during the Lowland Gorilla menstrual cycle

Sexual behaviors were recorded and urinary concentrations of total estrogens and pregnanediol-3-glucuronide (Pdg) measured during six normal menstrual cycles from two female lowland gorillas in a stable, captive group. Frequencies of female presentations, mounts, and copulations were positively associated with peak estrogen values but not with elevations of Pdg. These results support the observation that sexual behaviors in the gorilla occur most frequently in the periovulatory period and that copulations serve primarily a sexual function.

HEMATOLOGIC VALUES FOR TULE ELK (CERVUS ELAPHUS NANNODES)

Hematologic values for 99 tule elk (Cervus elaphus nannodes) from California (USA) are presented. These were obtained from individuals from three captures at Tomales Point (Point Reyes National Seashore, California) from 1997–98. Differences between capture groups were assessed. Greatest differences were detected between yearling bulls and cows in December 1998 which may be a reflection of age and reproductive status.