HISTOCHEMICAL DEMONSTRATION OF 3BETA-, 3ALPHA-, 11BETA-, AND 17BETA-HYDROXYSTEROID DEHYDROGENASES IN TESTIS OF FUNDULUS HETEROCLITUS

Testes of Fundulus heteroclitus were studied histochemically to localize the activity of 3β-, 3α-, 11β-, and 17β-hydroxysteroid dehydrogenases (HSD) and to explore the pattern of utilization of various hydroxysteroids by the testes in different stages of the sexual cycle. An activity for the enzymes studies was found mainly in the interstitial cells of the testis. Changes in the activity of enzymes occurred in relation to the reproductive cycle. In a testis in any specific stage, the intensity of the reactions obtained with different hydroxysteroids differed considerably. The majority of the 3β-hydroxysteroids employed as substrates were utilized, though to different extents, by the interstitial cells in all periods studied. The most intense enzyme reaction was recorded with 3β-hydroxy-5β-androstan-17-one or 3β-hydroxy-5α-androstan-17-one (epiandrosterone) as substrate. 3α-HSD activity was not only present in the interstitial cells but also in the epithelial cells of the efferent ducts as shown with 3α-hydroxy-5α-androstan-17-one; the enzyme activity in the interstitial cells was NAD-linked only, while the activity in the duct cells was both NAD- and NADP-linked. Among the 11β-hydroxy compounds used as substrates, 3α,11β-dihydroxy-5α-androstan-17-one (11β-hydroxyandrosterone) was the only steroid with which a distinct reaction was found in the interstitial cells; it was both NAD- and NADP-dependent. 17β-HSD activity could be detected in the interstitial cells in most of the periods of the sexual cycle with 3,17β-dihydroxyestra-1,3,5(10)-trien (17β-estradiol) or 17β-hydroxy-5α-androstan-3-one (5α-dihydrotestosterone) as substrate. 17β-Hydroxysteroid utilization was found to be NAD-linked only. © 1969.