engleski

EXPRESSION OF P-GLYCOPROTEIN (P-gp/Mdr1/Abcb1) IN RAT LIVER, KIDNEYS, AND GASTROINTESTINAL TRACT ; DISTRIBUTION AND SEX DIFFERENCES

P-gp is an ATP-dependent transmembrane efflux transporter constitutively expressed in the liver bile canaliculi (BC), renal proximal tubules (PT), intestinal epithelium, blood-tissue barriers, maternal-fetal barriers, and hematopoietic cells. In the BC, the P-gp expression exhibits sex differences (males (M)<females (F)), but the responsible hormone(s) causing these differences in the BC, and possibly in other P-gp expressing rat organs, have not been defined. Using a commercial monoclonal antibody, we studied effects of sex and gonadectomy on the localization and abundance of P-gp by immunocytochemistry and Western blotting in the liver, kidneys, and gastrointestinal tract of adult M and F rats. We confirmed sex differences (F>M) in the P-gp expression in BC ; gonadectomy in M, but not in F increased this expression. In the kidneys, the antibody stained the PT brush-border membrane ; gonadectomy in M, but not in F, decreased this expression in the cortex and increased in the outer stripe. In the intestine, the P-gp expression increased from proximal to distal segments, but sex differences or effects of gonadectomy were not observed. The data indicate that in rats, androgens inhibit the expression of P-gp in BC and PT S3 segments, and stimulate in the PT S2 segments.

P-glycoprotein; rat; sex differences

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