Schwartz J
Endocrinology. 1982 Dec;111(6):2087-90. doi: 10.1210/endo-111-6-2087.
Since acute treatment with antibodies to rat GH (ArGH) rapidly and specifically neutralizes the activity of circulating rat GH (rGH), the effect of rapid changes in GH status on protein synthesis was examined in diaphragm muscle from normal rats treated acutely with ArGH or control serum via an indwelling iv cannula. The incorporation of tritiated amino acids into muscle protein served as an index of protein synthesis. Rats were treated with serum twice in 3 h; 3 h later, the diaphragm muscle was incubated with [3H]leucine or [3H]phenylalamine. Under these conditions, the basal incorporation of the amino acids into muscle protein was lower after ArGH treatment. In these tissues, the addition of GH (5 micrograms/ml) in vitro restored protein synthesis to control levels within 90 min, whereas tissues from rats treated with control serum were not stimulated by the added GH. In all experiments, neutralization of the biological activity of GH by ArGH was verified by loss of the specific refractory effect of GH in adipose tissue from the same animals. Thus, neutralization of circulating GH by ArGH is accompanied by a reduction in basal protein synthesis in muscle from normal rats; added GH rapidly restores amino acid incorporation to normal levels. These findings suggest that in normal animals, endogenous GH participates in sustaining protein synthesis in muscle and that rapid changes in circulating GH are accompanied by rapid changes in protein synthesis in muscle.
由于用抗大鼠生长激素（ArGH）抗体进行急性治疗能迅速且特异性地中和循环中的大鼠生长激素（rGH）的活性，因此通过留置静脉插管对正常大鼠急性给予ArGH或对照血清，研究了生长激素状态的快速变化对蛋白质合成的影响。将氚标记的氨基酸掺入肌肉蛋白中作为蛋白质合成的指标。大鼠在3小时内接受两次血清处理；3小时后，将膈肌与[3H]亮氨酸或[3H]苯丙氨酸一起孵育。在这些条件下，ArGH处理后氨基酸掺入肌肉蛋白的基础水平较低。在这些组织中，体外添加生长激素（5微克/毫升）可在90分钟内将蛋白质合成恢复到对照水平，而用对照血清处理的大鼠的组织未受到添加的生长激素的刺激。在所有实验中，通过同一动物脂肪组织中生长激素特异性不应答效应的丧失，证实了ArGH对生长激素生物活性的中和作用。因此，ArGH对循环生长激素的中和作用伴随着正常大鼠肌肉中基础蛋白质合成的减少；添加生长激素可迅速将氨基酸掺入恢复到正常水平。这些发现表明，在正常动物中，内源性生长激素参与维持肌肉中的蛋白质合成，并且循环生长激素的快速变化伴随着肌肉中蛋白质合成的快速变化。
