Histological Studies on X-Zone of Adrenal Cortex: II. Fate of X-zone of Adrenal Cortex in Castrated Male Mice

The adrenal cortices of male mice of D. D. strain respectively castrated at the 10th and 40th postnatal day were histologically observed with a particular remark to the fate of X-zone and the results were as follows: Both organ and body weight tended to increase more exceedingly than those of non castrated control in the corresponding postnatal days, and in early castration group (10 day) they showed a more marked increase than in late castration group (40th day). In male mice early catrated, X-zone which is naturally destined to be shrunk on the normal course of postnatal development was succeeded conversely by the gradual proliferation inherent in the level of non-castrated female mice. The cell population of X-zone began to grow profoundly from the 15th day following the castration, and its consistuent cells became to be activated in their shape and internal structure. On the contrary a sign of degeneration in X-zone was concurrently brought with the augmentation in size and in 40 to 60 days the thorough involution appeared, resulting in atrophic pattern of X-zone. However this zone was inclined to increase in size again after the 90th day in equilibrium with the degree of degeneration. In lately castrated mice, X-zone which was to be naturally involuted on way of normal postnatal development grew in size and proliferated by the castration, but, being compared with the progressive change in early castration group, the morphological response in late castration was less serious and dilatory, presenting no formation of indepelndent cell layer with the precise border, but only simple cell groups scattered at the periphery of the medulla resembling the character of X-zone. The islet-like groups whichy consist of X-zone cells did not provide the active internal structure, and they were before long dispersed in the lapse of time. In a word the acting power to hypertrophy the X-zone by the castration was stronger in case of using the immature animals as the materials than in the event of using adult animals. As to the definition of X-zone, we prefer to formulate it as the independent cell layer providing the active cellular pattern in response to the internal environment of living body, rather than mere atrophic remainder of the fetal cortex. And despite any conclusion was not drawn from present investigation concerning what kind of hormones are secreted out of the X-zone and their hormonal regulation mechanism, we discussed these problems from the present issu