Ovarian prostaglandin levels at the midsequence oviposition, the terminal ovipostion and the first ovulation of a sequence in the hen (Gallus domesticus).

Abstract

Prostaglandin (PG) F and E levels in plasma and tissues were examined at the midsequence oviposition (CsOP), the terminal oviposition (CtOP) and the first ovulation (C1OV) of a sequence. PG levels were determined in (1) plasma from the brachial, uterine and three largest preovulatory folliclular veins, (2) theca and granulosa layers of the five largest preovulatory and three postovulatory follicles, and (3) myometrium and mucosa layers of the uterus. PGF levels in peripheral and uterine plasma were about the same between CsOP, CtOP and C1OV. At CsOP and C1OV, plasma PGF levels in the largest preovulatory follicle (F 1) were higher than those in the second (F 2) and third largest (F 3) follicles. On the other hand, PGF level in the F 1 plasma at CtOP was not higher than that in the F 2 plasma and lower than those in the F 1 plasma at CsOP and C1OV. The amounts of PGF detected in the theca layers at CsOP and C1OV increased with follicular growth reaching a maximum in F 1. In contrast, PGF level in the F 1 theca layer at CtOP was lower than those at CsOP and C1OV. However, PGF level in the theca layer of the largest postovulatory follicle (R 1) at CtOP increased to the same level in the F 1 theca at CsOP and C1OV. PGF level in the granulosa layer did not change with follicular size increase. PGE level of theca layer was high in F 2 and F 1 at each case, whereas PGE level in the granulosa layer did not change with follicular growth. PGF levels in the myometrium and mucosa layers were about the same through the three cases examined. These results suggest that in the cases of C1OV and CsOP, processes associated with ovulation may be related to PG synthesis in F 1, while only in the case of CtOP, R 1 may provide a signal for the terminal oviposition of a sequence, because it is not accompanied by the ovulatory process.