Histochemical localization of Δ⁵-3β -hydroxysteroid dehydrogenase and glucose-6-phosphate dehydrogenase in the testis of Indian skipper frog Rana cyanophlyctis (Schneider)

Abstract

The distribution of Δ⁵-3β -hydroxysteroid dehydrogenase (Δ⁵-3β -HSDH), glucose-6-phosphate dehydrogenase (G-6-PDH), TPNH- and DPNH-diaphorases were histochemically studied in the testis of skipper frog (Rana cyanophlyctis) throughout the year. Pregnenolone, 17α-hydroxypregnenolone, 16-dehydropregnenolone acetate, dehydroepiandrosterone (DHA), and etiocholanolone were used as the substrates for the demonstration of Δ⁵-3β-HSDH activity, which occurs mainly in the interstitial Leydig cells and also in the columnar cells of Sertoli, indicating their probable role in steroidogenesis. Both G-6-PDH and the TPNH-diaphorase show a distribution similar to that of Δ⁵-3β-HSDH but give intense reaction, whereas the distribution of DPNH-diaphorase is ubiquitous. No appreciable seasonal variation in the distribution of these enzymes has been observed. The significance of these findings and the substrate specificity of Δ⁵-3β-HSDH in the frog testis has been discussed.