Androgen and oestrogen concentrations in the ovary of the cyclic rat.
In the 5-day cyclic rat the ovarian androgen and oestrogen concentrations, measured by radioimmunoassay, started a gradual rise on the day of metoestrus, reaching maximal values in the period from 22.00 h on dioestrus 2 until 17.00 h on the day of pro-oestrus. A steep decline in the ovarian androgen and oestrogen concentrations occurred between 17.00 and 21.00 h on the day of pro-oestrus. Rats, injected intraperitoneally with an ovulation-blocking dose of pentobarbitone sodium (35 mg/kg body weight) at 13.00 h on the day of pro-oestrus, tended to show a decline in ovarian concentrations of androgens and oestrogens during the late pro-oestrus, but this decrease was less steep than in saline-injected rats. At 10.00 and 14.00 h on the day after pro-oestrus the ovarian concentrations of androgens and oestrogens in rats treated with pentobarbitone sodium showed a further decline but values were still higher than those in saline-treated oestrous rats. At 17.00 h, i.e. 28 h after injection with pentobarbitone sodium, a distinct increase in the ovarian androgen and oestrogen concentrations was noted and a steep decline was observed at 21.00 h on the day after pro-oestrus. Thus normal as well as delayed ovulation was preceded first by an increase and then by a steep decline in ovarian concentrations of oestrogens and androgens.
D000728:Androgens / Q000378:metabolism*; D000818:Animals; D004967:Estrogens / Q000378:metabolism*; D004971:Estrus; D005260:Female; D010053:Ovary / Q000187:drug effects / Q000378:metabolism*; D010424:Pentobarbital / Q000494:pharmacology; D011247:Pregnancy; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains
D000728:Androgens; D004967:Estrogens; D010424:Pentobarbital