Hypothalamic catecholamine metabolism in diabetic rats: the effect of insulin deficiency and meal ingestion.
The effect of moderate insulin deficiency of 2 weeks in duration on hypothalamic catecholamine metabolism in food-deprived and meal-fed rats was evaluated. Hypothalamic tyrosine content in food-deprived (from 0700 to 1600 h), diabetic rats was normal. Also normal were the rates of 3,4-dihydroxyphenylalanine accumulation following aromatic amino acid decarboxylase inhibition, norepinephrine and 3,4-dihydroxyphenylethylamine (dopamine) clearance after tyrosine hydroxylase inhibition, and intraneuronal amine accumulation following monoamine oxidase inhibition. Differences in hypothalamic amine metabolism were apparent, however, when diabetic and normal rats were fed 2-g meals. The 3-methoxy-4-hydroxyphenylethyleneglycol sulfate accumulation rate was depressed in diabetic rats by the carbohydrate meal but was stimulated by the tyrosine-supplemented protein meal. In contrast, the tyrosine-supplemented diet had no effect on 3,4-dihydroxyphenylacetic acid accumulation in diabetic animals, whereas the production rate in normal rats was increased. We conclude that normal responses occurring in hypothalamic catecholamine metabolism after the consumption of a meal are modified by the presence of diabetes.
Glanville
N T
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Anderson
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D000818:Animals; D065105:Aromatic Amino Acid Decarboxylase Inhibitors; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D004044:Dietary Proteins / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism*; D005502:Food; D005508:Food Deprivation; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D007328:Insulin / Q000502:physiology; D008297:Male; D008734:Methoxyhydroxyphenylglycol / Q000031:analogs & derivatives / Q000378:metabolism; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014443:Tyrosine / Q000378:metabolism / Q000494:pharmacology; D014446:Tyrosine 3-Monooxygenase / Q000037:antagonists & inhibitors
D065105:Aromatic Amino Acid Decarboxylase Inhibitors; D004044:Dietary Proteins; D007328:Insulin; D008996:Monoamine Oxidase Inhibitors; C030284:3-methoxy-4-hydroxyphenylglycol sulfate; D014443:Tyrosine; D008734:Methoxyhydroxyphenylglycol; D014446:Tyrosine 3-Monooxygenase; D004298:Dopamine; D009638:Norepinephrine