Sex differences in adrenocortical structure and function. XXIII. Time-studies on the long-term effects of gonadectomy...

The aim of the study was to investigate the changes in the size and function of the rat adrenal gland in relation to time-intervals elapsed from postpubertal gonadectomy. Eight weeks after testectomy absolute adrenal gland weights were higher than in intact rats. After that time gradual decrease in the weight was observed and at week 32 the weights were similar to that in intact rats. At weeks 8 and 12 after ovariectomy there was no change in the weight of the gland, however from week 16 onward a gradual decrease occurred. Corticosterone output by adrenal homogenate of orchiectomized rats was lower than in control male rats from week 24 of experiment while in ovariectomized rats such a drop was observed from week 12 of experiment. Activity of adrenal 5 alpha-reductase was markedly higher in either orchiectomized or ovariectomized rats as compared to intact rats at week 8 of experiment. After that time enzyme activity decreased reaching at weeks 24 and 32 control levels. This suggests that 5 alpha-reductase plays only transitional role in adaptation of adrenals to gonadectomy. Neither orchiectomy nor ovariectomy had significant effect on mitochondrial 11 beta-hydroxylase activity. Obtained results clearly show that gonadectomy-induced changes in rat adrenal depend upon time-interval elapsed from surgery. Moreover, they suggest that additionally to 5 alpha-reductase activity, also other factors induced by gonadectomy are responsible for the drop in corticosterone output by adrenals of gonad-deprived rats.