[Adrenocortical zonation in the laboratory Japanese field vole (Microtus montebelli)]

Adrenocortical zonation in the laboratory Japanese field vole (Microtus montebelli) was investigated histologically with special attention to the sex and species specific differences. The whole cortex and zona reticularis showed clear sex differences. They were thicker in females than in males. In this respect the vole was similar to the mouse and rat, but different from the Syrian hamster and mastomys. Male cortices were characterized by thick z. fasciculata and meagre z. reticularis, while both zones were thick in females. The z. fasciculata in both sexes and z. reticularis in females seemed to be divided into two sublayers by the cellular arrangement. No distinctive additional zones were identified. The histological observations indicated that the Japanese field vole might have interesting endocrinological characteristics and serve for studying the mechanism of the zone formation in the mammalian adrenal cortex.