Temporal coincidence of the appearance of elongated spermatids and of histochemical reaction of 11 beta-hydroxysteroid dehydrogenase in rat Leydig cells.

The serial semithin sections of the testes of perfused rats (age: 25-41 postnatal days) were evaluated microscopically on each alternative day for the morphology of spermatogenetic cells and especially for spermatid differentiation. The histochemical reaction for non-specific esterases, 3 alpha-hydroxysteroid-dehydrogenase (HSDH), 3 beta-HSDH, 11 beta-HSDH, 17 beta-HSDH were performed in cryostat sections of corresponding rat testes (age: 25-55 days). Eight different types of germ cell associations (designated as A-H) appeared from day 25 to day 41. Seven steps of differentiation of spermatids were characterized. The turning point of spermatid maturation was observed on day 35. Prior to this day, mainly spermatids step 1 were identified. On day 35 spermatids steps 1-5 were present. The reactions of non-specific esterases, 3 beta-HSDH, 17 beta-HSDH and 3 alpha-HSDH were observed in the Leydig cells of all testes. Only from day 35 onwards could 11 beta-HSDH be demonstrated. The temporal sequence of the differentiation of spermatids and the appearance of histochemical activity of 11 beta-HSDH in the Leydig cells seem to be closely correlated. An additional observation concerning the presence of germ cell debris was made in the seminiferous tubules during the postnatal development. Large amounts of debris were observed only till day 33.