Ultrastructural features of ovarian interstitial tissue in a wild mouse, Apodemus flavicollis, at various reproductive stages, with a note on its histochemistry at the onset of the breeding period

Abstract

In Apodemus flavicollis caught at the onset of the breeding season, interstitial tissue of the ovaries showed weak to moderate 3β-hydroxysteroid dehydrogenase and glucose-6-phosphate dehydrogenase activity. Interstitial cells were found to be actively secretory among females with open vaginas. The active cells were characterized by round nuclei and well-developed cytoplasmic organelles. The mitochondria were sometimes associated with smooth endoplasmic reticulum and had mainly tubular cristae. Lipid droplets were few and contained electron-dense material. A Golgi complex with associated vesicles was conspicuous, as were endo- or exo-cytotic vesicles. It is concluded that in A. flavicollis interstitial tissue is actively secretory in connection with ovulation or early pregnancy.