Adrenal cortex of Micromys minutus japonicus (Japanese harvest mouse). Its histochemical and fine structural study.

Micromys minutus japonicus (Japanese harvest mouse) is one of the smallest known mammals and is easily maintainable in the laboratory. The adrenal cortex of this animal is described here for the first time. The morphological structure with histochemistry was essentially the same as that of the mouse or the rat. However, the histochemical activity of steroid 3 beta-OH dehydrogenase in the zona glomerulosa was characteristically positive in this animal and electron microscopically Golgi's apparatus and endoplasmic reticulum were prominent in the glomerular cells. The concentration of aldosterone was high in the serum. These findings suggest the hyperfunction of the zona glomerulosa in this animal.