Umpleby A M, Russell-Jones D L
Department of Medicine, United Medical School, St Thomas' Hospital, London, UK.
Baillieres Clin Endocrinol Metab. 1996 Oct;10(4):551-70. doi: 10.1016/s0950-351x(96)80711-7.
While all the hormones described have regulatory effects on the rates of protein synthesis and breakdown there is a complex interaction between them in this control process. Insulin, GH and IGF-I play a dominant role in the day-to-day regulation of protein metabolism. In humans insulin appears to act primarily to inhibit proteolysis while GH stimulates protein synthesis. In the post-absorptive state IGF-I has acute insulin-like effects on proteolysis but in the fed state, or when substrate is provided for protein synthesis in the form of an amino acid infusion, IGF-I has been shown to stimulate protein synthesis. Growth hormone and testosterone have an important role during growth but continue to be required to maintain body protein during adulthood. Thyroid hormones are also required for normal growth and development. The hormones glucagon, glucocorticoids and adrenaline are all increased in catabolic states and may work in concert to increase protein breakdown in muscle tissue and to increase amino acid uptake in liver for gluconeogenesis. While increased glucocorticoids result in reduced muscle mass the effects of glucagon may be predominantly in the liver resulting in increased uptake of amino acids. In contrast to the catabolic effect of adrenaline on glucose and lipid metabolism, studies to date suggest that adrenaline may have an anti-catabolic effect on protein metabolism. Despite this adrenaline increases the production of the gluconeogenic amino acid alanine by muscle and its uptake by the splanchnic bed. There is considerable interest in the use of anabolic hormones, either alone or in combination, in the treatment of catabolic states. GH combined with insulin has been shown to improve whole-body and skeletal muscle kinetics while GH combined with IGF-I has a greater positive effect on protein metabolism in catabolic states than either hormone alone. If catabolic states are to be treated successfully a greater understanding of the role of the catabolic hormones in these states and the possible treatment of these states with anabolic hormones is required.
虽然上述所有激素都对蛋白质合成和分解速率具有调节作用，但在这一控制过程中它们之间存在复杂的相互作用。胰岛素、生长激素（GH）和胰岛素样生长因子-I（IGF-I）在蛋白质代谢的日常调节中起主导作用。在人类中，胰岛素似乎主要起抑制蛋白水解的作用，而生长激素则刺激蛋白质合成。在吸收后状态下，IGF-I对蛋白水解具有急性胰岛素样作用，但在进食状态下，或者当以氨基酸输注的形式为蛋白质合成提供底物时，IGF-I已被证明可刺激蛋白质合成。生长激素和睾酮在生长过程中起重要作用，但在成年期仍需要它们来维持身体蛋白质。甲状腺激素对于正常的生长和发育也是必需的。胰高血糖素、糖皮质激素和肾上腺素在分解代谢状态下都会增加，它们可能协同作用，增加肌肉组织中的蛋白质分解，并增加肝脏对氨基酸的摄取以进行糖异生。虽然糖皮质激素增加会导致肌肉量减少，但胰高血糖素的作用可能主要在肝脏，导致氨基酸摄取增加。与肾上腺素对葡萄糖和脂质代谢的分解代谢作用相反，迄今为止的研究表明，肾上腺素可能对蛋白质代谢具有抗分解代谢作用。尽管如此，肾上腺素会增加肌肉中糖异生氨基酸丙氨酸的产生及其被内脏床的摄取。单独或联合使用合成代谢激素来治疗分解代谢状态引起了人们的极大兴趣。已证明生长激素与胰岛素联合使用可改善全身和骨骼肌动力学，而生长激素与IGF-I联合使用在分解代谢状态下对蛋白质代谢的积极作用比单独使用任何一种激素都更大。如果要成功治疗分解代谢状态，就需要更深入地了解分解代谢激素在这些状态中的作用以及使用合成代谢激素对这些状态进行可能的治疗。
