The Zona Glomerulosa and Corticotrophin: A Genetic Study in Mice

Abstract

CBA/FaCam mice have adrenals with a well-developed zona glomerulosa. This zone is poorly developed in mice ofthe Peru strain, although the production of aldosterone is similar in the two strains. The zona glomerulosa was considerably reduced in CBA mice treated with synthetic corticotrophin (ACTH). In these mice degeneration of the adrenal X zone took the form typical of Peru mice. Treating Peru mice with dexamethasone resulted in the appearance of a wide zona glomerulosa, presumably as a consequence of lowered levels of ACTH in plasma. The hypothesis of relatively high levels of ACTH in Peru mice also received support from the relatively small spleens and large adrenals found in mice of this genotype. A significant negative correlation existed between the width of the zona glomerulosa and the weight of cortical tissue for the two strains and their F1 hybrid. This correlation did not, however, hold for mice of the genetically heterogeneous backcross generations. Thus the variation in the histological appearance of the subcapsular tissue was not causally related to differences in the mass of steroidogenic tissue.The relationships between the visibly differentiated zona glomerulosa, the cells that produce aldosterone, and their control systems are discussed in the light of theories about the relationship between structure and function in the adrenal glands.

Effect of Dexamethasone on Cell Population Kinetics in the Adrenal Cortex of the Prepubertal Male Rat

“…Wright (19716) and Wright et al (1973) have shown that in the prepubertal animal much cell pro¬ duction takes place in the z. glomerulosa, followed by migration of these cells to the inner zones. It is difficult to reconcile this concept of adrenocortical cytogenesis with the absence of ACTH control of cell proliferation in the z. glomerulosa, but the recent observations of Shire & Stewart (1972) have shown that at least in the mouse ACTH has a modifying effect on the morphology of the z. glomerulosa. The findings of Palkowitz & Mitro (1968) indicate that in prepubertal rats of this age an action of dexamethasone mediated by the hypophysial-pituitary-adrenal system is possible, and that depression of endogenous ACTH may play a part in the response.…”