“…Progesterone administration on the day before pro-oestrus in 5-day cycling adult female rats causes ovulating hormone release 24 hr earlier than normal (Everett & Sawyer, 1949b (Ramirez & McCann, 1964;Schwartz & Calderelli, 1965). Phénobarbital blocked the lh increase in the afternoon of pro-oestrus (Schwartz & Calderelli, 1965 (Cole, 1936;Strauss & Meyer, 1962 (Mills & Schwartz, 1961;Schwartz & Bartosik, 1962;Rennels & O'Steen, 1967) have been shown to decrease during the critical period and both exogenous lh and fsh can cause ovulation (Zarrow, Caldwell, Hafez & Pincus, 1958;Zarrow & Gallo, 1966 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 9/9 9/9 9/9 9/9Î 9/9t 9/9Î 9/9Î 0/9 0/9 0/9 0/9 0/9 9/9 9/9 9/9 9/9Í 0/12 11/11 12/12 9/9 10/llt 10/llt 13/13Î 12/12J (5/9)t (6/8) (4/9) (4/9) (4/9) (4/9) (7/9) (3/9) (4/9) (3/9) (0/9) (0/9) (0/9) (0/9) (0/9) (0/9) (0/9) (0/9) (7/9) (4/9) (3/9) (3/8) (1/9) (0/9) (0/9) (0/9) (0/9) (3/12) (1/ ) (1/12) (1/9) (1/11) (1/11) (0 (7/9) (9/9) (9/9) (9/9) (8/9) (8/9) (8/9) (8/9) (9/9) (8/9) (6/9) (0/9) (1/9) (1/9) (2/9) (4/9) (1/9) (3/9) (9/9) (9/9) (7/9) (9/9) (2/9) (0/9) (1/9) (0/9) (1/9) (8/12) (4/11) (7/12) (8/9) (7/11) (10/11) (6/13) (7 (Bogdanove, 1964). Therefore, in the 16.30 PB rat oh synthesis occurs.…”