Differential regulation of protein synthesis by amino acids and insulin in peripheral and visceral tissues of neonatal pigs |
| |
Authors: | Agus Suryawan Pamela M J O’Connor Jill A Bush Hanh V Nguyen Teresa A Davis |
| |
Institution: | (1) United States Department Agriculture/Agriculture Research Service, Department of Pediatrics, Children’s Nutrition Research Center, Baylor College of Medicine, 1100 Bates St, Houston, TX, 77030, USA; |
| |
Abstract: | The high efficiency of protein deposition during the neonatal period is driven by high rates of protein synthesis, which are
maximally stimulated after feeding. In the current study, we examined the individual roles of amino acids and insulin in the
regulation of protein synthesis in peripheral and visceral tissues of the neonate by performing pancreatic glucose–amino acid
clamps in overnight-fasted 7-day-old pigs. We infused pigs (n = 8–12/group) with insulin at 0, 10, 22, and 110 ng kg−0.66 min−1 to achieve ~0, 2, 6 and 30 μU ml−1 insulin so as to simulate below fasting, fasting, intermediate, and fed insulin levels, respectively. At each insulin dose,
amino acids were maintained at the fasting or fed level. In conjunction with the highest insulin dose, amino acids were also
allowed to fall below the fasting level. Tissue protein synthesis was measured using a flooding dose of l-4-3H] phenylalanine. Both insulin and amino acids increased fractional rates of protein synthesis in longissimus dorsi, gastrocnemius,
masseter, and diaphragm muscles. Insulin, but not amino acids, increased protein synthesis in the skin. Amino acids, but not
insulin, increased protein synthesis in the liver, pancreas, spleen, and lung and tended to increase protein synthesis in
the jejunum and kidney. Neither insulin nor amino acids altered protein synthesis in the stomach. The results suggest that
the stimulation of protein synthesis by feeding in most tissues of the neonate is regulated by the post-prandial rise in amino
acids. However, the feeding-induced stimulation of protein synthesis in skeletal muscles is independently mediated by insulin
as well as amino acids. |
| |
Keywords: | |
本文献已被 PubMed SpringerLink 等数据库收录! |
|