Abstract
Summary
The relation of the thyroid gland to estrogenic effects on adrenal corti-costerone secretion was examined in ovari-ectomized rats. Estradiol administration to castrates increased corticosterone output by increasing ACTH secretion and by decreasing adrenal 5α-reductase activity, diminishing the intra-adrenal conversion of corticosterone to 5α-reduced metabolites. When given to rats that were thyroidectomized as well as castrated, estradiol produced a far smaller increase in corticosterone secretion. The increment in corticosterone obtained in thyroidectomized rats was fully accounted for by the effects of estradiol on adrenal 5 a-reductase activity. The results indicate that effects of estradiol on adrenal secretion resulting secondarily from changes in ACTH secretion are thyroid-dependent, whereas direct effects on intraadrenal steroid reductive pathways are not.
The excellent technical assistance of Ms. Nancy Swygert and Ms. Marlene Pope is gratefully acknowledged. These studies were supported by Research Grants from NIH (AM-03370) and NSF (GB41215).
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