Morgan D G, Kulkarni R N, Hurley J D, Wang Z L, Wang R M, Ghatei M A, Karlsen A E, Bloom S R, Smith D M
ICSM Endocrine Unit at the Hammersmith Hospital, Imperial College School of Medicine, London, UK.
Diabetologia. 1998 Dec;41(12):1482-91. doi: 10.1007/s001250051095.
Neuropeptide Y (NPY) has been shown to inhibit insulin secretion from the islets of Langerhans. We show that insulin secretion in the insulinoma cell line RIN 5AH is inhibited by NPY. 125I-Peptide YY (PYY) saturation and competition-binding studies using NPY fragments and analogues on membranes prepared from this cell line show the presence of a single class of NPY receptor with a Y1 receptor subtype-like profile. Inhibition of insulin secretion in this cell line by NPY fragments and analogues also shows a Y1 receptor-like profile. Both receptor binding and inhibition of insulin secretion showed the same orders of potency with NPY > [Pro34]-NPY > NPY 3-36 >> NPY 13-36. The Y1 receptor antagonist, BIBP 3226, blocks NPY inhibition of insulin secretion from, and inhibits 125I-PYY binding to, RIN 5AH cells. Northern blot analysis using a Y1-receptor specific probe shows that NPY Y1 receptors are expressed by RIN 5AH cells. Y5 receptors are not expressed in this cell line. Neuropeptide Y inhibition of insulin secretion is blocked by incubation with pertussis toxin, implying that the effect is via a G-protein (Gi or Go) coupled receptor. Neuropeptide Y inhibits the activation of adenylyl cyclase by isoprenaline in RIN 5AH cell lysates, and the stimulation of cAMP by glucagon-like peptide-1 (7-36) amide (GLP-1). It also blocks insulin secretion stimulated by GLP-1, but not by dibutyryl cyclic AMP. Hence, we suggest that NPY inhibits insulin secretion from RIN 5AH cells via a Y1 receptor linked through Gi to the inhibition of adenylyl cyclase.
神经肽Y（NPY）已被证明可抑制胰岛β细胞分泌胰岛素。我们发现胰岛素瘤细胞系RIN 5AH的胰岛素分泌也受到NPY的抑制。使用NPY片段和类似物对该细胞系制备的膜进行的125I-肽YY（PYY）饱和及竞争结合研究表明，存在一类单一的NPY受体，其具有Y1受体亚型样特征。NPY片段和类似物对该细胞系胰岛素分泌的抑制作用也呈现出Y1受体样特征。受体结合及胰岛素分泌抑制实验均显示，NPY > [Pro34]-NPY > NPY 3-36 >> NPY 13-36的效力顺序相同。Y1受体拮抗剂BIBP 3226可阻断NPY对RIN 5AH细胞胰岛素分泌的抑制作用，并抑制125I-PYY与RIN 5AH细胞的结合。使用Y1受体特异性探针进行的Northern印迹分析表明，RIN 5AH细胞表达NPY Y1受体。该细胞系不表达Y5受体。用百日咳毒素孵育可阻断神经肽Y对胰岛素分泌的抑制作用，这意味着该效应是通过G蛋白（Gi或Go）偶联受体介导的。神经肽Y可抑制异丙肾上腺素对RIN 5AH细胞裂解液中腺苷酸环化酶的激活作用，以及胰高血糖素样肽-1（7-36）酰胺（GLP-1）对cAMP的刺激作用。它还可阻断GLP-1刺激的胰岛素分泌，但不影响二丁酰环化AMP刺激的胰岛素分泌。因此，我们认为NPY通过与Gi相连的Y1受体抑制RIN 5AH细胞的胰岛素分泌，进而抑制腺苷酸环化酶的活性。
