Neural Timing of Ovulation in Immature Rats

Science  14 Sep 1962:
Vol. 137, Issue 3533, pp. 860-861
DOI: 10.1126/science.137.3533.860


Treated with Gonadotrophin Thirty-two-day-old female rats, injected two days previously with gonadotrophin from pregnant mares' serum, were given barbiturate at different times during the afternoon to determine whether the ovulation that would occur the next day could be blocked. The results indicate that ovulation depends upon release of pituitary ovulating hormone during a"critical period" between 2 and 4 P.M.