Chronic loss of ovarian function decreases transport of leptin into mouse brain.

Loss of ovarian function, such as occurs with menopause in human beings and ovariectomy in rodents, results in weight gain. Using multiple-time regression analysis, a sensitive technique for quantifying blood-to-brain transport of peptides and polypeptides, we found that mice ovariectomized for at least 5 weeks had markedly reduced entry of the satiety factor leptin into brain. The rate of entry of leptin into brain remained reduced half a year later. The results suggest that the weight gain resulting from loss of ovarian function could be explained by decreased transport of leptin into the brain.