Studies on mechanisms of delayed puberty in female rats effected by dietary eicosapentaenoic acid

Abstract

Marine oils contain eicosapentaenoic acid, a fatty acid that competes for cyclooxygenase and reduces the synthesis of dienoic prostanoids including prostaglandin E2 (PGE2). Since PGE2 plays an important role in the release of hypothalamic GnRH and the maturation of ovarian follicles and ova release, it was postulated that a diet containing fish oil (FO) would delay first ovulation through inhibitory effects on GnRH release, follicle development and ovulation. Immature female Sprague-Dawley rats were fed a FO diet ad libitum. Controls were pair-fed an identical diet with the substitution of safflower oil. The age of the FO-fed rats was significantly increased at first estrus, and first ovulation was either delayed or inhibited. Preoptic area/hypothalamic and ovarian PGE2 levels were reduced by FO feeding whereas hypothalamic GnRH was significantly increased. A FO-containing diet may delay the onset of puberty through attenuation of preovulatory GnRH release and local impairment of the ovulatory process.