THYROID HORMONE ADMINISTRATION AND OVARIAN AND ADRENAL ACTIVITY IN RATS BEARING HYPOTHALAMIC LESIONS1

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Abstract
Bilaterally symmetrical electrolytic lesions which damaged arcuate nucleus and median eminence in the hypothalamus of adult female rats regularly produced atrophy of the reproductive tract (and reduced thyroid function) but were without consistent effect on adrenal morphology. Hypothalamic obesity and genital hypoplasia were frequently associated. Thyroxine and triiodothyronine administration to intact animals induced ovarian and uterine hypertrophy as well as adrenal enlargement. Similar treatment in operated rats failed to reverse the gonadal atrophy but did not interfere with the adrenal hypertrophy. A differential response was also found in rats made severely hypothyroid with propylthiouracil prior to hypothalamic destruction. Ovarian atrophy without concomitant change in adrenal cortex occurred following placing of lesions and goitrogen withdrawal. Evidences of adreno-cortical activation were seen in rats with diabetes insipidus (lesion-induced) and in chronically starved animals with marked hypothalamic deficit. The results signify that basal adenohypophysial ACTH secretion can be enhanced by chronic stress despite arcuate-median eminence lesions and that some aspects of thyro-ovarian interaction may be mediated through a hypothalamic-hypophysial component.