Catecholamines in ovarian follicles during the ovulatory cycle of White Leghorn hens.

Dopamine (DA) concentrations in the largest ovarian follicle (F1) showed significant decrease at 12 and 8 h prior to ovulation. Nor-epinephrine (NE) and epinephrine (E) concentrations in the F1, sampled at different times of the ovulatory cycle, were found to increase with the approach of ovulation time. However, the concentration of epinephrine in the F1 was low just after oviposition compared with the immediate two previous stages investigated. The concentrations of DA, NE and E in the second largest follicles (F2) did not vary significantly during the ovulatory cycle. Average concentration of DA was low and that of NE and E high in the F1 compared with the respective concentrations in the F2.