DISTRIBUTION OF RAT HEPATIC-STEROID 5-ALPHA-REDUCTASE-1 AS SHOWN BY IMMUNOHISTOCHEMISTRY

Peptide fragments of rat liver 5 alpha-reductase were synthesized acco rding to the published primary sequence data. The peptides were used ( i) in free form and (ii) linked to keyhole limpet hemocyanin (KLH), re spectively, for immunization of rabbits. Resulting antisera showed pos itive reaction with the respective peptide-antigen in an ELISA. In Wes tern blot experiments the antisera specifically recognized a 26,000 mo l wt protein in extracts from female and male rat liver. All antisera, as well as isolated immunoglobulins, showed inhibition of 5 alpha-red uctase activity in microsomes prepared from rat liver. Positive immuno histochemical reactions were observed in the perinuclear cytoplasm of hepatocytes. No reaction was seen in Kupffer- and connective tissue ce lls. Acinar heterogeneity of the immunoreaction was seen in the male r at liver with a gradient from the portal canal to the central vein. Af ter androgen-deprivation a considerable increase in immunoreactivity w as seen in male rat liver cells, indicating androgen-dependent suppres sion of the enzyme in male liver.