[The morphofunctional characteristics of the testicular interstitial endocrinocytes in the red suslik (Citellus major Pallas) during a seasonal change in reproductive activity].

Light and electron microscopy, morphometric methods were used for studying Leydig cells of Citellus major Pallas from Orenburg Province populations in seasonal changing. Dynamics of structural changes in certain parameters of testis (area of interstitial tissue of the section, diameter of seminiferous tubules, endocrinocyte number, their nuclear volume, the state of structural components of the cytoplasm) in seasonal changing of the reproductive activity was shown. The highest functional activity of Leydig cells was noted during the reproduction period (the beginning of April) and before the onset of hibernation period. However, Leydig cells activity decreases insignificantly during the reproductive activity decline and it remains elevated during spring and summer.