Midcycle and luteal elevations of follicle stimulating hormone in squirrel monkeys (Saimiri boliviensis) during the estrous cycle

Abstract

Follicle stimulating hormone (FSH) has fundamental importance in reproductive function, but its cyclic pattern has not previously been described in the squirrel monkey, due primarily to the lack of a suitable assay. An homologous radioimmunoassay (RIA) based on recombinant cynomolgus FSH measured changes in serum FSH relative to patterns of bioactive luteinizing hormone (LH), estradiol, and progesterone during the estrous cycle. FSH was observed to have a sharp peak during the late follicular phase coincident with the LH surge and then rose again during the luteal phase. Estradiol was low except for the midcycle rise, suggesting an inhibitory relationship. The rat granulosa cell in vitro FSH bioassay confirmed high levels of this hormone. Measurement of FSH in the squirrel monkey has found a pattern different from Old World primates in the luteal phase, which may provide insight into the reproductive mechanisms of this species. Am. J. Primatol. 52:207–211, 2000. © 2000 Wiley‐Liss, Inc.

Nonhuman Primates

“…Hormone analysis of S. b. boliviensis show a peak elevation in follicle-stimulating hormone (FSH) during the late follicular stage that coincides with the luteinizing hormone (LH) surge, and a second FSH peak occurs during the luteal phase (Yeoman et al, 2000). Serum concentrations of estradiol (E 2 ), progesterone (P), and squirrel monkey chorionic gonadotropin (SMG) can be used to diagnose early pregnancy in squirrel monkeys.…”