Sharma S K, Austin C, Howard A, Lo G, Nicholl C G, Legon S
Department of Chemical Pathology, Royal Postgraduate Medical School, Hammersmith Hospital, London, U.K.
J Mol Endocrinol. 1992 Dec;9(3):265-72. doi: 10.1677/jme.0.0090265.
Gastric inhibitory peptide (GIP) is a 42 amino acid gastrointestinal peptide which inhibits gastric acid secretion and stimulates pancreatic insulin secretion in the presence of glucose. Here we report the sequence of the cDNA encoding the rat GIP precursor. PreproGIP was 144 amino acids in length and comprised the GIP peptide itself, N- and C-terminal flanking peptides of 22 and 59 amino acids respectively and a typical hydrophobic signal peptide. The sequence indicated that GIP is released from its precursor by cleavage at single arginine residues. The C-terminal flanking peptide may have an important function since it was well conserved and contained a region of 16 amino acids with only a single, conservative replacement. Rat GIP mRNA was found in the duodenum and jejunum. Levels of GIP mRNA in the duodenum were increased twofold after a period of 2 days of starvation. There was no detectable expression of the GIP gene in other parts of the gastrointestinal tract or in other endocrine tissues. However, in pancreatic mRNA preparations, a larger mRNA was detected after low stringency hybridization. This could represent a further member of this gene family.
胃抑制肽（GIP）是一种由42个氨基酸组成的胃肠肽，在有葡萄糖存在的情况下，它能抑制胃酸分泌并刺激胰腺胰岛素分泌。在此我们报道编码大鼠GIP前体的cDNA序列。前胰高血糖素原长度为144个氨基酸，由GIP肽本身、分别含22个和59个氨基酸的N端和C端侧翼肽以及一个典型的疏水信号肽组成。该序列表明GIP是通过在单个精氨酸残基处切割从前体释放出来的。C端侧翼肽可能具有重要功能，因为它高度保守，且含有一个由16个氨基酸组成的区域，仅有一个保守性置换。在十二指肠和空肠中发现了大鼠GIP mRNA。饥饿2天后，十二指肠中GIP mRNA水平增加了两倍。在胃肠道的其他部位或其他内分泌组织中未检测到GIP基因的表达。然而，在胰腺mRNA制剂中，低严谨度杂交后检测到一个更大分子量的mRNA。这可能代表该基因家族的另一个成员。
