A histochemical study of 3(beta)-sterol dehydrogenase in the adrenal cortex of the developing mouse.

The function of the X-zone of the adrenal cortex of the mouse has long been problematic. Howard ('39) suggested that this zone might function in androgen secretion under certain circumstances. This contention, however, is by no means certain (Jones, '57). Attempts to characterize this zone enzymatically have done little to clarify its functional status. Allen ('58 and '59) found that both aliesterase and DPNdiaphorase reached maximum activity levels in the X-zone about the 14th day of age. After this time the activities of these enzymes declined. The results suggested emergence of some functional activity prior to the 14th day of age which might be associated with either lipid or oxidative metabolism. No inference relating to secretory activity could be drawn from these studies. Recent development of a histochemical method for the localization of 3(9)sterol dehydrogenase (Wattenberg, '58) has made possible the visualization of enzymatic activity associated with certain phases of steroidogenesis. Application of this method to the study of the X-zone might be expected to yield information relating to the capacity of this area for the formation of intermediates in the synthesis of particular steroid hormones. The present paper deals with histochemically determined 3( B)-sterol dehydrogenase activity in the X-zone and permanent cortex of the adrenal gland of developing mice.