Induction of Prolactin Liver Receptors in the Male Rat

The induction of prolactin (Prl) liver receptors in the male rat by subfractions of human growth hormone (hGH) was studied. A heterogeneous preparation of hGH, devoid of immunoassayable Prl activity was fractionated by preparative isoelectric focusing (IEF). Induction of Prl receptors and the metabolism of 4-(4-14C)-andostene-3, 17-dione (A4) were studied in the liver microsomal fraction following continuous adminstration of the subfractions at a rate of 2.5 ug/h for one week. Induction of Prl receptors was noted with several subfractions which differed in their immunoreactivity. There was a relation between the Prl receptor induction and the A4 metabolism. Serum levels of testosterone (T) 5α-dihydrotestosterone (DHT) and of triglycerides (TG) appear to be unrelated to Prl receptor induction.