The effect of prolactin on reproductive function in female Japanese quail (Coturnix coturnix japonica).

The anti-gonadal or anti-gonadotropic actions of prolactin in Japanese quail (Coturnix coturnix japonica) were re-investigated. Treatment of mature regularly laying quail with 16 I.U. of ovine prolactin (NIH-P-S11) per day for 7 or 14 days caused significant (P less than .05) decreases in ovarian and oviductal weight and a reduction in egg production by the third day of treatment. The most frequent response to prolactin was complete cessation of ovulation for the duration of the experiment, but some birds showed no effects from the hormone treatment. Prolactin caused a significant (P less than 0.05) increase in body weight of the quail. Serum LH, measured during the expected time of the preovulatory LH surge, was significantly lower in birds treated with prolactin the day before sampling than in control birds. It was concluded that prolactin has a distinct anti-gonadal or anti-gonadotropic action in this species.