Fate of the granulosa cells in the hen's follicle

Summary In an early growing follicle the single row of granulosa cells are in apposition — they have abundant Golgi substance and granular endoplasmic reticulum. During growth the granulosa cells become separated by wide intercellular spaces filled with perivitelline substance. The granulosa cells of the mature follicle immediately preceding ovulation have an agranular reticulum and numerous lipid droplets. Granulosa cells can be identified up to 72 h after ovulation. During the 72 h the cytoplasm becomes progressively replaced by lipid. The initial change in intracellular structure may indicate a shift in function towards production of progesterone followed by fatty degeneration preceding their final disintegration.