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外文期刊>The biochemical journal
>The regulation of growth hormone secretion from the isolated rat anterior pituitary in vitro. The role of adenosine 3′:5′-cyclic monophosphate
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The regulation of growth hormone secretion from the isolated rat anterior pituitary in vitro. The role of adenosine 3′:5′-cyclic monophosphate
p1. The release of growth hormone from isolated fragments of rat anterior pituitary tissue incubated iin vitro/i was studied by employing a double-antibody radioimmunoassay. 2. In the absence of added stimuli, two phases of hormone release could be distinguished, an early phase of 2h duration and a subsequent late phase. In the early phase, hormone release was rapid but could be significantly decreased by calcium depletion and by 2,4-dinitrophenol whereas the rate of release in the late phase was uninfluenced by these incubation conditions. These results have been interpreted as indicating the existence of a secretory component in the early phase of release. 3. In subsequent experiments, the effects of various agents on the rate of hormone output during the late phase of incubation were investigated. Hormone release was increased by theophylline and by dibutyryl cyclic AMP (iN/isup6/sup-2′-iO/i-dibutyryl-adenosine 3′:5′-cyclic monophosphate), the response to both of these agents being related to the concentration of the stimulant employed. 4. The stimulation of growth hormone output by theophylline was significantly decreased by calcium deprivation and by 2,4-dinitrophenol. The response to dibutyryl cyclic AMP was diminished by 2,4-dinitrophenol, iodoacetate and 2-deoxyglucose but not by malonate or colchicine. 5. Arginine, β-hydroxybutyrate, albumin-bound palmitate and variation in the glucose concentration of the incubation medium over a wide range were without any statistically significant effect on the rate of hormone release from either control pituitary fragments or those subject to secretory stimulation by dibutyryl cyclic AMP. 6. It is suggested that the regulation of growth hormone secretion is mediated by cyclic AMP (adenosine 3′:5′-cyclic monophosphate). The secretion observed in response to cyclic AMP requires the presence of ionized calcium and a source of metabolic energy but is independent of pituitary protein synthesis ide novo/i. The integrity of the glycolytic pathway of glucose metabolism appears to be essential for cyclic AMP-stimulated growth hormone secretion to occur./p
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机译：> 1。采用双抗体放射免疫分析法研究了体外培养的大鼠垂体前叶组织分离片段中生长激素的释放。 2.在没有额外刺激的情况下，可以区分激素释放的两个阶段，即持续2h的早期阶段和随后的晚期阶段。在早期阶段，激素释放很快，但是可以通过钙耗竭和2,4-二硝基苯酚显着降低，而在这些培养条件下，晚期阶段的释放速率不受影响。这些结果已被解释为表明在释放的早期存在分泌成分。 3.在随后的实验中，研究了各种试剂在孵育后期对激素输出速率的影响。茶碱和二丁酰基环AMP（ N 6 -2'- O -二丁酰基-腺苷3'：5'-环一磷酸），对这两种药物的反应都与所用刺激剂的浓度有关。 4.钙缺乏和2,4-二硝基苯酚显着降低了茶碱对生长激素输出的刺激。 2,4-二硝基苯酚，碘乙酸盐和2-脱氧葡萄糖降低了对二丁酰基环状AMP的反应，但丙二酸或秋水仙碱则没有。 5.精氨酸，β-羟基丁酸酯，白蛋白结合的棕榈酸酯和温育培养基中葡萄糖浓度的变化在很宽的范围内，对对照垂体碎片或受到分泌刺激的垂体激素释放速率均无统计学意义。二丁酰基环状AMP。 6.建议生长激素分泌的调节是由环状AMP（腺苷3′：5′-环状单磷酸酯）介导的。观察到的响应环状AMP的分泌需要离子钙的存在和代谢能量的来源，但不依赖于垂体蛋白的合成。葡萄糖代谢的糖酵解途径的完整性似乎对环AMP刺激的生长激素分泌的发生至关重要。
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