Monosaccharide transport into lactating-rat mammary acini.
The uptake and release of 3-O-methyl-D-[3H]glucose at 37 degrees C by acini, prepared from lactating-rat mammary gland with collagenase, was inhibited by glucose, phloretin, cytochalasin B, HgCl2 and low temperature. Uptake and phosphorylation of 2-deoxy-D-[3H]glucose, studied in greater detail, could be ascribed to a specific, saturable, inhibitable, process of apparent Km 16 mM and Vmax. approx. 56 nmol/min per mg of protein, plus a non-specific, non-inhibitable process that was monitored with [14C]fructose. The mean rate of uptake of 5 mM-2-deoxyglucose (16 nmol/min per mg of protein) was similar to the rate of consumption of 5 mM-glucose, suggesting that transport was a rate-limiting step in the overall metabolism of glucose. This accords with evidence for a glucose gradient across the plasma membrane.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D003571:Cytochalasin B / Q000494:pharmacology; D003847:Deoxyglucose / Q000378:metabolism; D005260:Female; D006593:Hexokinase / Q000378:metabolism; D007774:Lactation; D008321:Mammary Glands, Animal / Q000187:drug effects / Q000378:metabolism*; D008627:Mercuric Chloride; D008628:Mercury / Q000494:pharmacology; D009005:Monosaccharides / Q000378:metabolism*; D010693:Phloretin / Q000494:pharmacology; D011247:Pregnancy; D051381:Rats
D009005:Monosaccharides; D003571:Cytochalasin B; D008627:Mercuric Chloride; D003847:Deoxyglucose; D006593:Hexokinase; D008628:Mercury; D010693:Phloretin