Abstract
Summary
The effects of 21 days of constant illumination on the hypothalamic content of FSH-RF and on pituitary content and concentration of FSH were studied in two groups of intact adult female rats. Control rats were housed under standard light conditions (14 hours of light daily). In the rats under constant light, hypothalamic FSH-RF content was significantly increased whereas pituitary FSH content and concentration remained unchanged. Pituitary and uterine weights were increased, and ovarian weight was decreased. Histological examination of the ovaries of the constant light treated rats showed large numbers of well-developed follicles with few small corpora lutea. The uteri of these rats showed a marked augmentation in vascularity, muscle mass, number of glands in the endometrium, and increased height of the epithelium. These results suggest that constant light stimulates increased release of FSH from the pituitary by increasing hypothalamic production of FSH-RF.
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