Department of Animal Physiology and Biochemistry, Poznan University of Life Sciences, Poznan, Poland.
Physiol Res. 2009;58(6):863-871. doi: 10.33549/physiolres.931467. Epub 2008 Dec 17.
Adenosine is secreted from adipocytes, binds to adenosine A(1) receptor and modulates various functions of these cells. In the present study, the effects of an adenosine A(1) receptor antagonist (DPCPX; 0.01, 0.1 and 1 microM) on lipogenesis, glucose transport, lipolysis and the antilipolytic action of insulin were tested in rat adipocytes. DPCPX had a very weak effect on lipogenesis and did not significantly affect glucose uptake. In adipocytes incubated with 1 microM DPCPX, lipolysis increased. This effect was blunted by insulin and by a direct inhibitor of protein kinase A. Moreover, 0.1 microM DPCPX substantially enhanced the lipolytic response to epinephrine and increased cAMP in adipocytes. However, DPCPX was ineffective when lipolysis was stimulated by direct activation of protein kinase A. Adipocyte exposure to epinephrine and insulin with or without 0.1 microM DPCPX demonstrated that this antagonist increased the release of glycerol. However, despite the presence of DPCPX, insulin was able to reduce lipolysis. It is concluded that DPCPX had a weak effect on lipogenesis, whereas lipolysis was significantly affected. The partial antagonism of adenosine A(1) receptor increased lipolysis in cells incubated with epinephrine alone and epinephrine with insulin due to the synergistic action of 0.1 microM DPCPX and epinephrine.
腺苷从脂肪细胞中分泌出来，与腺苷 A(1) 受体结合，调节这些细胞的各种功能。在本研究中，检测了一种腺苷 A(1) 受体拮抗剂 (DPCPX；0.01、0.1 和 1 μM) 对大鼠脂肪细胞的脂肪生成、葡萄糖转运、脂肪分解和胰岛素的抗脂肪分解作用的影响。DPCPX 对脂肪生成的作用很弱，对葡萄糖摄取没有显著影响。在孵育 1 μM DPCPX 的脂肪细胞中，脂肪分解增加。这种作用被胰岛素和蛋白激酶 A 的直接抑制剂所减弱。此外，0.1 μM DPCPX 显著增强了肾上腺素引起的脂肪分解反应，并增加了脂肪细胞中的 cAMP。然而，当脂肪分解通过直接激活蛋白激酶 A 刺激时，DPCPX 无效。脂肪细胞暴露于肾上腺素和胰岛素，无论是否存在 0.1 μM DPCPX，均表明该拮抗剂增加了甘油的释放。然而，尽管存在 DPCPX，胰岛素仍能降低脂肪分解。结论是 DPCPX 对脂肪生成的作用较弱，而脂肪分解则受到显著影响。由于 0.1 μM DPCPX 和肾上腺素的协同作用，腺苷 A(1) 受体的部分拮抗剂增加了单独用肾上腺素和肾上腺素加胰岛素孵育的细胞中的脂肪分解。
