Effect of estradiol-17 beta on glucose and proline uptake in plasma membrane vesicles from the R3230AC rat mammary carcinoma.
Purified plasma membrane vesicles isolated from R3230AC rat mammary tumors displayed carrier-mediated and stereospecific uptake. Uptake was shown to be proportional to protein concentration, sensitive to increasing osmolarity, and inhibited only by substrates entering by the same carrier. Carrier-mediated glucose uptake was inhibited rapidly by estradiol-17 beta and phloretin in a dose-dependent manner, whereas proline uptake was not affected by estradiol-17 beta. The data suggest that the inhibition of glucose by estradiol and phloretin, originally observed in whole cells, occurs by an interaction of the steroid with a component on the plasma membrane. In contrast, the lack of effects of estradiol on proline transport into vesicles implies that intracellular components may have mediated the estrogen-induced effects observed in whole cells.
D019325:3-O-Methylglucose; D000818:Animals; D001667:Binding, Competitive; D001692:Biological Transport / Q000187:drug effects; D002462:Cell Membrane / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D005947:Glucose / Q000378:metabolism*; D007700:Kinetics; D008325:Mammary Neoplasms, Experimental / Q000378:metabolism*; D008757:Methylglucosides / Q000378:metabolism; D010693:Phloretin / Q000494:pharmacology; D011392:Proline / Q000378:metabolism*; D051381:Rats; D012964:Sodium / Q000494:pharmacology
D008757:Methylglucosides; D019325:3-O-Methylglucose; D004958:Estradiol; D011392:Proline; D012964:Sodium; D005947:Glucose; D010693:Phloretin