Hypotensive action of prolactin in rats with spontaneous hypertension

Rats (SHR) weighing 240 +/- 10 g with spontaneous hypertension were given intraperitoneally porcine prolactin in doses from 0.2 to 2000 micrograms/kg of body weight. The systolic pressure was measured before hormone administration and 2 hours after it. It was found that prolactin in doses of 200 to 2000 micrograms/kg caused a decrease of the systolic pressure by 22%. The dose of 20 micrograms/kg decreased this pressure by 9% and the dose of 0.2 microgram/kg by 7.9%.