IMMUNOCHEMICAL DISTRIBUTION AND IMMUNOHISTOCHEMICAL LOCALIZATION OF 20-BETA-HYDROXYSTEROID DEHYDROGENASE IN NEONATAL PIG-TISSUES

Immunochemical distribution of 20 beta-hydroxysteroid dehydrogenase (H SD) in neonatal pig tissues was investigated by Western blot analysis of the proteins reacting with anti-20 beta-HSD antibody. 20 beta-HSD w as present in all organs investigated: brain, lung, thymus, submandibu lar gland, heart, liver, kidney, spleen, adrenal gland, testis, epidid ymis, prostate, vas deferens and seminal vesicle. In particular, high concentrations of 20 beta-HSD were detected in the testis, followed by the kidney and liver, by the [I-125]-protein A binding method. Immuno histochemical localization of the enzyme was achieved in paraffin sect ions of the testis, kidney, liver, epididymis, and vas deferens by the streptoavidin-biotin complex method. In the testis, very strong immun ostaining was found only in interstitial Leydig cells, whereas the cel ls in seminiferous tubules, such as Sertoli cells and spermatogenic ce lls, were entirely negative. In the kidney, strong immunostaining was detected in epithelial cells of Henle's loop. The immunoreactive prote ins were also localized in the hepatic lobules of the liver, tall colu mnar cells of the ductus epididymidis of the epididymis, and mucosal e pithelium cells and muscularis of the vas deferens. These observations indicate that tissue distribution of 20 beta-HSD is similar to that o f carbonyl reductase in the human and rat. However, the specific and a bundant expression of 20 beta-HSD in testicular Leydig cells of the ne onatal pig, which are concerned with the synthesis of androgens, sugge sts that 20 beta-HSD has a very important physiological role in testic ular function during the neonatal stage. Copyright (C) 1996 Elsevier S cience Ltd.