EFFECT OF ESTROUS CYCLE AND FEMALE SEX STEROIDS on LEPTIN IN FEMALE RATS

Leptin, a hormonal product of the obese (ob) gene Pays an important role in the control of reproduc-ton. Reproductive Steroids, such as estrogen and ndrogens regulate fat distribution in the body. Te present Study was performed to evaluate the mene of estrous cycle and the sex steroids,realty °stradiol (E2) and progesterone on the a cone . Sixty-four adult female albi-me eper . throughout the experiments. In phase i the rats were segregated into nd oa the estrous cycle by vaginal rent of sen were collected for Steron | ma leptin, estrogen and pro-ited in fm experiment, the rats were 0 fy STOUps, each of eight rats. The esate oil ous Were injected with vehicle toy “Stradio} benzoate (Sugskg b. wt) “topes “Proate (2me/kg b. wt) srad,» and estrad- generously daily for sevendays, respectively and plasma leptin was meas-ured. Leptin levels in female rats showed non-significant differences during the estrous cycle. A positive correlation existed between the plasma leptin level and the body weight among the phas-cs of estrous cycle. There was no correlation be-tween leptin level and both estrogen and progeste-rone levels during the estrous cycle. Estrogen treatment significantly increased the plasma leptin concentration, while progesterone or estrogen plus progesterone treatments had no effect. The present study demonstrated that 17B-estradiol can regulate leptin secretion in female rat and the physiological variations of circulating estrogen and progesterone have no significant effect on the leptin level during normal estrous cycle.