Different absorption behaviors among steroid hormones due to possible interaction with P-glycoprotein in the rat small intestine. |
| |
Authors: | A Nakayama O Eguchi M Hatakeyama H Saitoh M Takada |
| |
Institution: | Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Kanazawa, Japan. |
| |
Abstract: | The intestinal absorption of ten steroid hormones was evaluated in the rat small intestine, especially focusing on the interaction with intestinal P-glycoprotein (P-gp). Hydrocortisone, prednisolone, 6alpha-methylprednisolone, and dexamethasone (adrenocortical steroid hormones) all disappeared in a regional-dependent manner (duodenum>jejunum>ileum). The decreased rate of disappearance in the lower small intestine seemed to be due to the involvement of absorption barriers like P-gp. In contrast, all sex hormones including progesterone exhibited very high absorbability in the entire small intestine (duodenum=jejunum=ileum), possibly demonstrating the absence of restricted absorption by intestinal P-gp. Progesterone enhanced the rate of disappearance of vinblastine but did not affect 6alpha-methylprednisolone. In the presence of vinblastine and verapamil, on the other hand, the rate of disappearance of 6alpha-methylprednisolone increased significantly. It was demonstrated that there was a plural P-gp family, which had different substrate specificities, in the rat intestine and that steroid hormones interacted with them as substrates or inhibitors in a very complex manner. |
| |
Keywords: | |
|
|