THE EFFECT OF CENTRAL ADMINISTRATION OF PROLACTIN ON FOOD-INTAKE IN VIRGIN FEMALE RATS IS DOSE-DEPENDENT, OCCURS IN THE ABSENCE OF OVARIAN HORMONES AND THE LATENCY TO ONSET VARIES WITH FEEDING REGIMEN

Lactation in mammals is characterized by a marked hyperphagia and sign ificantly elevated levels of prolactin (PRL). Several recent experimen ts in our laboratory have provided evidence for a causal relationship between PRL and hyperphagia. The present series of studies revealed th at PRL injected intracerebroventricularly (i.c.v.) twice daily for ten days to free feeding virgin female rats produced a dose-dependent inc rease in food intake without disrupting vaginal cyclicity, that the hy perphagic effect of centrally administered PRL was not dependent on th e presence of ovarian hormones, that it did not selectively potentiate feeding during the light or dark phase of the daily light cycle and t hat the latency of the feeding response to i.c.v. PRL administration w as shorter in food restricted animals. Taken together, these results s upport the idea that PRL acts centrally to potentiate food intake.