title: Control of glucose metabolism in isolated acini of the lactating mammary gland of the rat. The ability of glycerol to mimic some of the effects of insulin.
abstract: Inhibition of glucose uptake by acetoacetate and relief of this inhibition by insulin found previously in slices of rat mammary gland [Williamson, McKeown & Ilic (1975) Biochem. J. 150. 145-152] was confirmed in acini, which represent a more homogeneous population of cells. Glycerol (1mM) behaved like insulin (50 minuits/ml) in its ability to relieve the inhibition of glucose (5 mM) utilization caused by acetoacetate (2 mM) in acini. Both glycerol and insulin reversed the increase in [citrate] and the decrease in [glycerol 3-phosphate] and the [lactate]/[pyruvate] ratio in the presence of acetoacetate. Lipogenesis from 3H2O, [3-14C] acetoacetate, [1-14C]- and [6-14C]-glucose was stimulated, whereas 14CO2 formation from [3-14C]acetoacetate was decreased. Neither insulin nor glycerol relieved the acetoacetate inhibition of glucose uptake when lipogenesis was inhibited by 5-(tetradecyloxy)-2-furoic acid. From measurements of [3-14C]acetoacetate incorporation into lipid in the various situations it is suggested that a cytosolic pathway for acetoacetate utilization may exist in rat mammary gland. In the absence of acetoacetate, glycerol inhibited glucose utilization by 60% and increased both [glycerol 3-phosphate] and the [lactate/[pyruvate] ratio. Possible ways in which glycerol may mimic the effects of insulin are discussed.
mesh_terms: D000090:Acetoacetates / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D002264:Carboxylic Acids / Q000494:pharmacology; D005227:Fatty Acids / Q000096:biosynthesis; D005260:Female; D005663:Furans / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism*; D005990:Glycerol / Q000494:pharmacology*; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology*; D007774:Lactation; D050356:Lipid Metabolism; D008321:Mammary Glands, Animal / Q000187:drug effects / Q000378:metabolism*; D011247:Pregnancy; D051381:Rats
chemical_list: D000090:Acetoacetates; D002264:Carboxylic Acids; D005227:Fatty Acids; D005663:Furans; D007328:Insulin; C014289:5-(tetradecyloxy)-2-furancarboxylic acid; D005947:Glucose; D005990:Glycerol