INFLUENCE OF ENDOGENOUS LEPTIN TONE ON THE ESTROUS-CYCLE AND LUTEINIZING-HORMONE PULSATILITY IN FEMALE RATS

Recent data indicate that leptin may well play an important regulatory role in the hypothalamo-pituitary-gonadal axis. In order to further u nravel the mechanisms by which leptin acts, we have studied the effect of treatment (8 days) of leptin antiserum (5 mu l daily; i.c.v.) on L H pulsatility and estrous cycle in adult female rats. The administrati on of leptin antiserum led to a marked decrease in LH pulsatility as a ssessed by the area under the curve (13.5 +/- 4.7 ng/ml) in comparison to rats treated with normal rabbit serum (114 +/- 53 ng/ml; p < 0.01) . Furthermore, rats treated with leptin antiserum showed an impairment of reproductive function as shown by the fact that all rats remained in anestrus. In conclusion, these data show that leptin markedly influ ences LH secretion and the estrous cycle in the female rat.