ULTRASTRUCTURAL CHANGES IN THE OVARIES OF INFANT MICE DEPRIVED OF ENDOGENOUS GONADOTROPHINS AND AFTER SUBSTITUTION WITH FSH

Abstract

Summary. The ultrastructure of ovaries of infant mice deprived of gonadotrophins was compared to the normal developmental pattern and to that of animals deprived of endogenous gonadotrophins but receiving FSH. In the absence of circulating gonadotrophins, structural changes were observed ; granulosa-cell nuclei were irregularly shaped rather than round, and the spaces between the granulosa cells disappeared as did the spaces between the granulosa cells and the oocyte. The most striking effect was observed in the zona pellucida, the width of which diminished and became irregular. The number of cell processes within the zona pellucida was markedly reduced. These changes are tentatively attributed to alteration in the structure of the granulosa cell. Substitution with FSH partly prevented these changes, indicating that FSH has a rôle to play in the preservation of the integrity of the granulosa-cell membrane.