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

• Published in: Theriogenology 2010-03, Vol.73 (4), p.468-473
• Main Authors: Hernández-López, L., Cerda-Molina, A.L., Chavira-Ramírez, R., Mondragón-Ceballos, R.
• Format: Article
• Language: English
• Subjects: 17beta-estradiol; animal age; Ateles; Ateles geoffroyi; estradiol; Fecal 17β-estradiol; Fecal progesterone; feces; females; Menopause; ovulation; progesterone; Reproductive senescence; Spider monkey
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/j.theriogenology.2009.09.029

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.