Adrenal cortex in retired breeder Mongolian gerbils (Meriones unguiculatus) and golden hamsters (Mesocricetus auratus).

Alterations occur predominantly in cells of the zona reticularis in retired breeder Mongllian gerbils and golden hamsters. In gerbils, the size and number of lipid droplets increased and numerous large lipid-lysosomal complexes were observed in zona reticularis parenchymal cells or in macrophages, which were more numerous than in younger animals. Abundant lipofuchsin pigment was observed in zona reticularis parenchymal cells, and mitochondria contained electron-opaque inclusions. In the hamster, lipid droplets were present in inner zona reticularis cells and there was an increased amount of pigment within macrophages. Some of the alterations in gerbils and hamsters may at least in part reflect a stimulation of zona reticularis cells in retired breeders, attributable to increased prolactin secretion.