Available reports on adrenal function following unilateral adrenalectomy mainly concern the gland's activity under basal conditions. Its response to superadded stress has largely escaped attention. The present communication deals with changes in morphology and in the behavior of acid phosphatase, non-specific esterases and 3beta-hydroxysteroid dehydrogenase in solitary adrenal glands following operative trauma. Histochemical, electrophoretic and biochemical techniques have been employed in the study. Although the morphological response to identical trauma on both unilaterally adrenal-extomized and intact animals is indistinguishable, the enzymological response is strikingly different in the two groups. While in the latter, the enzyme activities exhibit an early rise following trauma, the same is delayed by another 8 hr in the former. In experments using ACTH, the overall pattern of exterase activity shows little deviation from that observed in untreated cases in both groups of animals. The findings indicate that in unilaterally adrenalectomized animals, susperadded operative stimuli fail to evoke the early response characteristic of the normal adrenal glands. Such latency points to the vulnerability of their existing defence mechanisms. The remarkable similarity of adrenal response with or without exogenous ACTH in these animals suggests that the reason for a delayed response is rooted in the target organ itself, and is not due to an altered plasma ACTH level.
