Feldman D, Hirst M
Am J Physiol. 1978 Aug;235(2):E197-202. doi: 10.1152/ajpendo.1978.235.2.E197.
Studied were performed to examine the factors that might regulate phosphoenolpyruvate carboxykinase (PEPCK) activity in rat brown adipose tissue (BAT) and to determine the role played by glucocorticoids in regulating this enzyme. Comparison was made to white adipose tissue (WAT) where PEPCK activity is known to be glucocorticoid regulated. PEPCK activity in BAT did not respond to adrenalectomy or dexamethasone, whereas WAT activity was increased and decreased, respectively, by these maneuvers. Three conditions were found in which BAT PEPCK activity was stimulated: 1) fasting, 2) feeding a high-fat/low-carbohydrate diet, and 3) during the neonatal period. In each case glucocorticoid treatment prevented the stimulation in PEPCK activity and restored the enzyme to base-line levels. In conditions 1 and 2, enzyme activity was also stimulated in WAT, but in contradistinction to BAT, glucocorticoid administration reduced activity to low levels significantly below base-line activity. Two conditions were found which suppressed PEPCK activity in BAT: exposure to a cold environment and feeding a high-protein/low-fat diet. WAT PEPCK was unaltered by exposure to cold. Thus, differences in PEPCK regulation between BAT and WAT were demonstrated, and the response to glucocorticoids was unique in BAT.
开展研究以检测可能调节大鼠棕色脂肪组织（BAT）中磷酸烯醇式丙酮酸羧激酶（PEPCK）活性的因素，并确定糖皮质激素在调节该酶中所起的作用。将其与白色脂肪组织（WAT）进行比较，已知WAT中的PEPCK活性受糖皮质激素调节。BAT中的PEPCK活性对肾上腺切除术或地塞米松无反应，而WAT中的活性则分别因这些操作而增加和降低。发现有三种情况可刺激BAT中的PEPCK活性：1）禁食，2）喂食高脂肪/低碳水化合物饮食，3）在新生儿期。在每种情况下，糖皮质激素治疗均可阻止PEPCK活性的刺激，并使该酶恢复至基线水平。在情况1和2中，WAT中的酶活性也受到刺激，但与BAT不同的是，给予糖皮质激素可将活性显著降低至低于基线活性的低水平。发现有两种情况可抑制BAT中的PEPCK活性：暴露于寒冷环境和喂食高蛋白/低脂肪饮食。暴露于寒冷环境对WAT中的PEPCK没有影响。因此，证明了BAT和WAT之间PEPCK调节的差异，并且BAT对糖皮质激素的反应是独特的。
