Tutwiler G F
Biochim Biophys Acta. 1975 Sep 8;404(1):18-29. doi: 10.1016/0304-4165(75)90143-9.
Bovine diabetogenic protein has been further purified by gel filtration yielding a fraction (Mr 25 000--28 000) having increased diabetogenic and in vitro lipolytic activity. Using rat epididymal fat pads, this fraction was shown to be lipolytic at concentrations as low as 1--10 mug/ml. The in vitro lipolytic effect was unaffected by the nutritional state of the animals, was not potentiated by dexamethasone, could be demonstrated in the presence and absence of glucose and was not mediated by alpha- and beta-adrenergic receptors. A lag phase of greater than 1 h was observed before diabetogenic protein induced lipolysis occurred, suggesting that protein synthesis might be involved. Cycloheximide (10 mug/ml), added initially, prevented the diabetogenic protein-induced lipolysis. This direct effect of the purified protein on adipose tissue helps explain the elevation of free fatty acids seen when bovine diabetogenic hormone is administered in vivo and suggests that this anterior pituitary protein may be a new lipid-mobilizing hormone.
牛致糖尿病蛋白已通过凝胶过滤进一步纯化，得到一个组分（相对分子质量25000 - 28000），其致糖尿病活性和体外脂解活性增强。使用大鼠附睾脂肪垫，该组分在低至1 - 10微克/毫升的浓度下就表现出脂解作用。体外脂解作用不受动物营养状态的影响，地塞米松不能增强其作用，在有葡萄糖和无葡萄糖的情况下均可表现出来，且不受α和β肾上腺素能受体介导。在致糖尿病蛋白诱导的脂解作用发生之前，观察到超过1小时的延迟期，这表明可能涉及蛋白质合成。最初加入的环己酰亚胺（10微克/毫升）可阻止致糖尿病蛋白诱导的脂解作用。纯化蛋白对脂肪组织的这种直接作用有助于解释在体内给予牛致糖尿病激素时所见到的游离脂肪酸升高现象，并提示这种垂体前叶蛋白可能是一种新的脂质动员激素。
