The efflux from and the metabolism of 3H-norepinephrine in sow Graafian follicles. Variable involvement of some prostaglandins during two different stages of the sex cycle.

The influences of acetylsalicylic acid (ASA) and of prostaglandins (PGs) E1, E2 or F2 alpha, on the spontaneous total tritium efflux from and on the metabolism of 3H-norepinephrine (3H-NE) in the walls of sow Graafian follicles isolated during two different stages of the sex cycle, were studied. The total 3H efflux from preparations obtained in proestrus (early preovulatory period) was higher than the output from diestrous tissues. This augmentation observed in proestrous samples, mainly attributable to a greater metabolism of 3H-NE, was expressed by an enhanced 3H-efflux corresponding to 3H-O-methylated (3H-OMDA) and 3H-normetanephrine (3H-NMN) metabolites. With regard to 3H-labelled compounds retained in the tissue, the follicular walls in proestrus (as compared to those in diestrus), retained more 3H-NMN fraction and less 3H-NE; an augmented metabolism of 3H-NE is suggested for the proestrous follicles. In the presence of ASA (2.2 X 10(-4) M) the above mentioned profiles of early preovulatory follicles, disappeared and the addition in vitro of PGE1 or PGE2 (10(-8) M), but not of PGF2 alpha (10(-8) M to 10(-6) M) was able to reverse the influence of ASA. These findings suggest the involvement of estrogens in the metabolism of 3H-NE by sow ovarian follicles and moreover, they also appear to indicate the requirement for some PGs, such as PGE1 and PGE2, generated by cells of the follicular wall.