Plasma concentrations of oestradiol-17 and progesterone, and laparoscopic observations of the ovary in the puma (Felis concolor) during oestrus, pseudopregnancy and pregnancy

Publisher Website
Google Scholar
Abstract
Plasma levels of estradiol and progesterone in 3 pumas during estrus and artificially induced pregnancy and pseudopregnancy were determined by radioimmunoassay. During estrus, basal levels of estradiol (5-30 pg/ml) were interrupted by surges of 30-375 pg/ml at intervals of 17-25 days. Considerable variation occurred between and within animals. Periods of estrus and follicular development were confirmed by laparoscopy and vaginal smear patterns. Absence of an increase in plasma progesterone following elevated levels of estradiol and failure to observe corpora lutea in the ovary indicated that ovulation was probably not spontaneous. Plasma estradiol values rose dramatically in response to pregnant mare serum gonadotropin but were low during pseudopregnancy until the return to estrus. During pregnancy, surges of estradiol occurred at mid-term and immediately before parturition. Ovulation, confirmed by laparoscopy, occurred 24-48 h after human chorionic gonadotropin and progesterone levels (usually < 2 ng/ml) then increased to reach 150-300 ng/ml on days 24-28. In the pseudopregnant animals progesterone concentrations had returned to baseline by days 45-50; during pregnancy, progesterone remained elevated, declining only gradually to basal values by day 85. A minor peak of progesterone, coincident with the pre-partum estradiol surge, occurred on day 87, 1 wk before parturition on day 95.