van Putten J P, Krans H M
Am J Physiol. 1985 Jun;248(6 Pt 1):E706-11. doi: 10.1152/ajpendo.1985.248.6.E706.
Catecholamines are known to have short-term regulatory effects on fat cell hexose uptake. We examined the long-term effects of catecholamines on the insulin-sensitive 2-deoxyglucose (dGlc) uptake in cultured 3T3-L1 adipocytes. Prolonged exposure (48 h) to isoproterenol (beta-adrenergic agonist) stimulated the basal dGlc uptake up to 90%. The effect was specific, time, concentration, and protein synthesis dependent and reversible. The effect of insulin was unaltered and superimposed on the increase in basal dGlc uptake. The long-term effect of isoproterenol was mimicked by epinephrine, dibutyryl cAMP (DBcAMP), and 1-methyl-3-isobutylxanthine (IBMX). By contrast, short-term exposure to isoproterenol (and epinephrine) induced a protein synthesis-independent increase in basal dGlc uptake (30%) not accompanied by an increase in insulin responsiveness. Moreover, on short-term basis, DBcAMP and IBMX suppressed both the basal and insulin-stimulated uptake up to 50%. Determination of the intracellular nonphosphorylated dGlc during the uptake and of the hexokinase activity revealed that the long-term effect of isoproterenol was most likely due to alterations low in dGlc transport. In conclusion, long-term regulators of hexose uptake are in cultured 3T3-L1 adipocytes, isoproterenol, and other cAMP stimulators. The long-term effect is independent from the short-term regulatory effect of the agents and from the effect of insulin.
已知儿茶酚胺对脂肪细胞己糖摄取具有短期调节作用。我们研究了儿茶酚胺对培养的3T3-L1脂肪细胞中胰岛素敏感的2-脱氧葡萄糖（dGlc）摄取的长期影响。长时间（48小时）暴露于异丙肾上腺素（β-肾上腺素能激动剂）可使基础dGlc摄取增加高达90%。该作用具有特异性、时间依赖性、浓度依赖性和蛋白质合成依赖性，且是可逆的。胰岛素的作用未改变，并叠加在基础dGlc摄取的增加之上。肾上腺素、二丁酰环磷腺苷（DBcAMP）和1-甲基-3-异丁基黄嘌呤（IBMX）可模拟异丙肾上腺素的长期作用。相比之下，短期暴露于异丙肾上腺素（和肾上腺素）可导致基础dGlc摄取出现与蛋白质合成无关的增加（30%），且胰岛素反应性未增加。此外，在短期内，DBcAMP和IBMX可使基础和胰岛素刺激的摄取抑制高达50%。在摄取过程中测定细胞内非磷酸化dGlc以及己糖激酶活性表明，异丙肾上腺素的长期作用很可能是由于dGlc转运降低所致。总之，在培养的3T3-L1脂肪细胞中，己糖摄取的长期调节因子是异丙肾上腺素和其他环磷腺苷刺激剂。长期作用独立于这些药物的短期调节作用以及胰岛素的作用。
