Initial studies on the administration route of prolactin.

The influence of administration route of prolactin on its biological availability in rats was determined. Prolactin was administered intraperitoneally, intramuscularly and intranasally (intranasal inhalation) in single doses of 2.5 mg/kg body weight. Within 5 hours after the administration, there were noticed evident differences in prolactin concentrations in blood dependening on the route of administration. The maximal prolactin concentration after its intraperitoneal administration was 1.5 times as high as the maximal concentration observed for intramuscular or intranasal administration. The area under the curves: concentration: intraperitoneal administration time and concentration: intramuscular administration time was 132.99 ng/cm3/h and 136.28 ng/cm3/h, respetively. The area under the curve (AUC0-&) for the intranasal administration of prolactin was not much different than for the intraperitoneal and intramuscular ones, and was 111.30 ng/cm3/h.