Abstract # 2336 Poster # 25:

Scheduled for Thursday, June 19, 2008 05:00 PM-07:00 PM: Session 4 (Ball Rooms A and B) Poster Presentation

Perimenopausal hormonal patterns in western lowland gorillas

S. Atsalis1 and S. Margulis1,2
1Lincoln Park Zoo, 2001 N. Clark, Chicago, IL 60614, USA, 2The University of Chicago
     The significance of the perimenopausal life stage and associated changing levels of reproductive hormones on the health of aging female primates requires further examination. While investigating reproductive hormone cycling patterns in zoo-living western lowland gorillas, Gorilla gorilla gorilla (n=30), applying non-invasive fecal hormone analyses, we discovered that approximately 1/3 of females >30 years old exhibited variable hormonal patterns suggesting perimenopause. Three females showed increased cycle variability, sometimes displaying protracted noncycling periods. Three females had low rises of progestogens or luteal insufficiency, possibly indicative of anovulatory cycling. Comparing the ratio of highest peak progesterone value in one luteal phase to lowest peak value in another, two females had unusually variable and high ratios. Concentrations of progestogens decreased from control to geriatric cycling and finally to menopausal females [F(2,26)= 3.58, p<0.05]. Mean levels of progestogens in perimenopausal females were lower than in normally cycling females. Thus, distinct differences exist between hormonal patterns of females who are cycling normally, those who are menopausal, and those who are cycling but exhibiting irregular patterns. Overall, results suggest age-related declines, consistent with perimenopause in human females. Osteoporosis and cardiovascular disease associated with premenopausal estrogen deficits in macaques strongly influence postmenopausal health, suggesting that it is important to investigate the impact of reproductive hormonal changes on health and fertility in the growing cohort of geriatric primates in zoos.