The Effect of Estrogen Hormone on Leptin Receptor in Small Intestine of Ovariectomized Rats

Leptin, a 16 kDa hormone encoded by the ob gene, is known for its role in the regulation of food intake, body composition and energy expenditure. Leptin receptor expression has been showed in several tissues including small intestine. There is a few data about the expression of leptin receptor in the small intestine and these data are contradictory. In the present study we detected the expression of leptin receptor in the small intestine using the methods of immunohistochemistry. Leptin receptor expression was found in villi and crypt epithelium of small intestine and in brunner gland of duodenum. While the strong reaction was essentially observed in base of the crypt, weak reaction was determined in differentiated upper region of the crypt and villi. Estrogen is known to influence different functions on the small intestine contain estrogen receptor. We have aimed to elucidate the effects of 17 ß estradiol (E2) on leptin receptor in the small intestine of ovariectomized rats, a model of postmenopausal condition. Ovariectomized rats were apportioned into three control (C18, C90, C162) and three estrogen groups (E18, E90, E162) (n=6 each) to evaluate time dependent effect of estrogen. 0.2 ml sesame oil to control group, 25 ? g 17 ß-estradiol to estrogen group were administrated. Rats were killed by cervical dislocation at 18, 90 and 162 hours resprectiveley. Duodenum, jejenum and ileum samples were removed and stained using immunohistochemistry. In ovariectomized rat, E2 administrtion increased the leptin receptor expression on epithelium of villi and crypt in duodenum and jejunum at 90 hours (p<0,05); and ileum at18 hours (p<0.05); and also on epithelium of villi in duodenum at 162 hours (p<0.05). These results indicated that E2 may upregulate the expression of leptin receptor in small intestine where glucose and other nutrients are absorbed after food intake and digestion; and also regulate intestine fuctions like digestion, absorbtion and secretion of mucin, in this wise.