Enzymhistochemical and morphometrical studies on delta 5-3 beta-hydroxysteroid dehydrogenase during the fetal and neonatal development of rat Leydig cells.

The aim of the present report was to study the course of development of rat Leydig cells from 17 fetal day (f.d.) up to 5 postnatal day (p.n.d.), with the help of enzymhistochemical reaction of delta 5-3 beta Hydroxysteroid-dehydrogenase (3 beta-HSDH). Testes were obtained from 17 to 21 days old embryos and from 1 to 5 days old offsprings. Cryostat sections were cut and processed for enzymhistochemical reaction of 3 beta-HSDH, employing dehydroepiandrosterone as substrate. The areas of the Leydig cells, showing the enzymatic activity, were measured morphometrically. The 3 beta-HSDH positive intertubular Leydig cells appear on 17 f.d., and grow further showing a maximum peak, relative to the size of the testis, on 19 f.d. Thereafter, the percentage of the Leydig cells relative to the size of the testis decreases continuously up to 4 p.n.d.. The Leydig cells did not regress during the period of observation. Postnatally, the large complexes disperse into many small complexes.