Effect of glutamate on the control of fatty-acid synthesis in white adipose tissue of the rat. Inhibition of pyruvate dehydrogenase.
Glutamate (5mM) inhibited glucose conversion to fatty acids by approximately one-third in adipocytes from fed rats. This inhibition was significantly less in the pressence of pyruvate or 2-oxoglutarate. After incubation of adipose tissue from fed rats with glucose and insulin, pyruvate dehydrogenase activity was 180 plus or minus 17 mU/g wet weight. Addition of glutamine to the incubation medium decreased this activity significantly (118 plus or minus 14 mU/g wet weight). This inhibition by glutamate was also diminished when 2-oxoglutarate or pyruvate were present. Glutamate added to homohentates of adipose tissue had no effect on the activation of pyruvate dehydrogenase by Mg-2+. However, glutamate inhibited the active form of the enzyme and enhanced the rate of inactivation of the enzyme complex by ATP and Mg-2+. Aminooxyacetate, a transaminase inhibitor, did not reverse the effects of glutamate on pyruvate dehydrogenase nor fatty acid synthesis.
D000273:Adipose Tissue / Q000187:drug effects / Q000201:enzymology*; D000409:Alanine / Q000494:pharmacology; D000641:Ammonia / Q000494:pharmacology; D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D004822:Epididymis; D005227:Fatty Acids / Q000096:biosynthesis*; D005650:Fumarates / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism; D005971:Glutamates / Q000494:pharmacology*; D066298:In Vitro Techniques; D007656:Ketoglutaric Acids / Q000494:pharmacology; D007773:Lactates / Q000378:metabolism; D008274:Magnesium / Q000494:pharmacology; D008293:Malates / Q000494:pharmacology; D008297:Male; D010710:Phosphates / Q000494:pharmacology; D011768:Pyruvate Dehydrogenase Complex / Q000037:antagonists & inhibitors*; D011773:Pyruvates / Q000378:metabolism; D051381:Rats; D013386:Succinates / Q000494:pharmacology; D013997:Time Factors
D005227:Fatty Acids; D005650:Fumarates; D005971:Glutamates; D007656:Ketoglutaric Acids; D007773:Lactates; D008293:Malates; D010710:Phosphates; D011768:Pyruvate Dehydrogenase Complex; D011773:Pyruvates; D013386:Succinates; D001224:Aspartic Acid; D000641:Ammonia; D008274:Magnesium; D005947:Glucose; D000409:Alanine