PMID: 8603768Apr 1, 1996Paper

Hyperglucagonemia stimulates phenylalanine oxidation in humans

Diabetes
P TessariA Tiengo

Abstract

Glucagon stimulates in vitro liver phenylalanine (Phe) degradation, thus inducing net protein catabolism. Whether these effects occur also in vivo in humans is not known. Therefore, we studied the effects of physiological hyperglucagonemia on Phe rate of appearance (Ra), hydroxylation, and oxidation in seven normal volunteers during infusions of somatostatin with replacement doses of insulin and growth hormone. Steady-state Phe kinetics were evaluated using the L-[1-14C]Phe tracer both at the end of a 3-h basal glucagon replacement period (glucagon concentration: 212 +/- 115 ng/l) and after a 3-h hormone infusion at the rate of approximately 3 ng x kg-1 x min-1 (--> 654 +/- 280 ng/l). Hyperglucagonemia did not change plasma Phe concentration and Ra but increased Phe oxidation by approximately 30% (P < 0.01). Oxidation was also increased by approximately 24% (P < 0.01) using plasma [14C]tyrosine (Tyr) specific activity as a precursor pool. Phe hydroxylation to Tyr estimated by assuming a fixed ratio of Tyr to Phe Ra (0.73) did not change. Nonhydroxylated Phe disposal decreased by approximately 6% (P = 0.08). These data show that in humans in the postabsorptive state, hyperglucagonemia, with near maintenance of basal insulin and ...Continue Reading

Citations

Jul 6, 2000·Journal of Physiology and Biochemistry·J A MartínezG Frühbeck
Jul 23, 1999·Annals of the New York Academy of Sciences·H WuC K Colton
Feb 15, 2003·Journal of Pediatric Endocrinology & Metabolism : JPEM·Nurit KaiserRafael Nesher
Jul 31, 2018·Endocrine Reviews·Karen D CorbinUNKNOWN Advancing Care for Type 1 Diabetes and Obesity Network (ACT1ON)
Apr 12, 2014·Nutrition Research Reviews·Laura MarroquíIvan Quesada
Apr 27, 2002·The American Journal of Clinical Nutrition·Paolo TessariElisabetta Iori
Apr 11, 2018·Molecular Neurobiology·Ashish K Rehni, Kunjan R Dave
Oct 1, 1996·The American Journal of Physiology·P TessariB Beaufrere
Jun 17, 1998·Metabolism: Clinical and Experimental·R BarazzoniP Tessari
Jun 17, 1998·Metabolism: Clinical and Experimental·A BattezzatiD E Matthews

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