Fig. 7.

Progesterone release in vitro by endometrial and myometrial slices harvested from pigs during days 10 to 11, 12 to 13 and 15 to 16 of pregnancy (n=4 in each period) and the estrous cycle (n=4 in each period). Slices were preincubated for 18 h and subsequently incubated for 12 h. Data are expressed as the mean ± SEM. Different small letters (a, b, c) indicate statistical differences in P₄ secretion from tissues within one examined period (P<0.05). Asterisks (**) indicate statistical differences in P₄ secretion from the same tissues during corresponding days of pregnancy and the estrous cycle (** 0.001<P<0.01).