Neonatal treatment with antiserum to prolactin lowers blood pressure in rats.

Prolactin administration reportedly increases blood pressure in rats and rabbits. To study the effects of prolactin deficiency on blood pressure, rats were given saline, normal rabbit serum, or rabbit antiserum to rat prolactin on postnatal days 2 to 5. Both males and females given antiserum had significantly lower blood pressure at 14 weeks than rats given saline or normal rabbit serum. Blood pressure differences between females given antiserum and females given saline disappeared during and following pregnancy. The antiserum also lowered the concentration of prolactin in plasma 49 percent in males and decreased the prolactin response to ether stress in both sexes. These results suggest that endogenous prolactin is involved in blood pressure regulation.