Operant food intake in pigs following intracerebroventricular (i.c.v.) administration of prolactin.

1. It has previously been shown that systemic administration of prolactin stimulates food intake in a number of animal species. 2. In the present study we investigated whether central administration of prolactin would increase food intake in satiated pigs trained to make operant responses for food and water. 3. Prolactin (25-100 U) administered by intracerebroventricular (i.c.v.) injection produced no significant effects on food intake during the 60 min measurement period after injection. 4. Furthermore, none of these doses of prolactin had any effect on the daily (24 hr) consumption of food in these animals. 5. Similarly prolactin (25-100 U) i.c.v. had no significant short or long-term effects on water intake. 6. These results indicate that prolactin does not stimulate food intake in pigs by a central mode of action.