[The morphofunctional characteristics of the interstitial endocrinocytes (Leydig cells) of the testes in vertebrates under conditions of seasonal change in reproductive activity].

By means of light and electron microscopy the structural organization of Leydig cells was studied in Rana ridibunda, Lacerta agilis, Columba livia in the periods of reproductive activity and reproductive break. The dynamics of structural changes of some parameters of the testicles (interstitial tissue square, endocrinocytes number, state of the cytoplasm, structural components and the volume of nuclei) was shown in the process of the reproductive activity seasonal changes. Nuclear volume and the degree of the agranular endoplasmic reticulum development were found to correlate. Clear dependence between the Leydig cells functional activity and reproductive activity in lizards and pigeons was demonstrated. This dependence is slightly expressed in frog.