Histology and Histogenesis of the Adrenal Cortex in the Guinea Pig.

Abstract

1. The adrenal cortex of the guinea pig is divided into three zones on the basis of structural differences; namely, glomerulosa, fasciculata and reticularis.
2. The glomerulosa develops from the narrow outer zone which is first distinguishable in the 3 cm embryo, and attains an almost definite structure in the 8.5 cm stage of embryonal life.
3. The glomerulosa shows little essential changes w ith sex and age.
4. The glomerulosa consists of cells arranged in irregularly shaped masses, which are enclosed in a delicate connective tissues and surrounded by many capillaries. The glomerulosa cells have a relatively large amount of cytoplasm, which contains extremely fine lipoid granules. Their nuclei present a characteristic feature of special interest, that is, nuclear deformation.
5. The histological pictures of the glomerulosa highly suggest that the cells of this zone have reached a high degree of differentiation, and therefore lend indirect support to the recent view that this zone actually has the secretory function.
6. The fasciculata develops from the broad inner zone that occupies a great portion of the cortex in the 3 cm embryo. This zone reaches an almost definite condition in cell character at the end of embryonal life, but its radially directed cords develop gradually after 3 to 5 days of age.
7. In the adult, the width of the fasciculata seems to be different in the two sexes, but the difference is not so definitive as in the reticularis.