In:
American Journal of Physiology-Endocrinology and Metabolism, American Physiological Society, Vol. 274, No. 3 ( 1998-03-01), p. E484-E492
Abstract:
We have measured skin and muscle protein kinetics and amino acid (AA) transport in anesthetized rabbits during 1) 64-h fast, 2) AA infusion, 3) AA plus fat emulsion infusion, and 4) AA plus hyperinsulinemia.l-[ ring- 13 C 6 ]phenylalanine was infused as the tracer, and the ear and hindlimb were used as arteriovenous units to reflect skin and muscle protein kinetics, respectively. Skin protein net balance was not different from zero in all groups, indicating a maintenance of protein mass. In contrast, the muscle net balance differed over a range from −1.6 ± 0.6 after fasting to 0.2 ± 0.2 μmol ⋅ 100 g −1 ⋅ h −1 during hyperinsulinemia. In the skin, 59–66% of intracellular free phenylalanine came from proteolysis, and phenylalanine availability from proteolysis was positively correlated to the protein synthesis rate. In conclusion, normal skin maintains its constant protein mass by efficient reutilization of AAs from proteolysis. In contrast to muscle, skin protein is relatively insensitive to control by nutritional and hormonal factors. Because of the metabolic differences, when limb models are used for muscle protein metabolism, the potential contribution by limb skin should be considered.
Type of Medium:
Online Resource
ISSN:
0193-1849
,
1522-1555
DOI:
10.1152/ajpendo.1998.274.3.E484
Language:
English
Publisher:
American Physiological Society
Publication Date:
1998
detail.hit.zdb_id:
1477331-4
SSG:
12
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