Synthesis of Mucus Glycoprotein in Ribosome of Rat Gastric Mucous Cell.

利用专门参与分泌o -糖苷糖蛋白（mucin）合成的胃粘膜细胞，研究了蛋白核心合成与脂肪酸酰化、n -乙酰半乳糖胺酰化、o -糖化的关系。[^<14>C]-半乳糖胺，然后分离肽肽-tRNA并释放新生肽，表明新生肽已在大鼠胃粘膜细胞核糖体中糖基化和酰化1。研究了乙醇和前列腺素对胃粘膜细胞糖蛋白合成的影响。用[^3H]-脯氨酸、[^3H]-棕榈酸、[^<14>C]-半乳糖胺对大鼠胃粘膜细胞进行乙醇和前列腺素El存在下的短期组织培养。低浓度乙醇（0.05 ~ 0.1 m）刺激了糖蛋白合成，较高浓度乙醇（0.5 ~ 1.5 m）使糖蛋白合成明显减少。在乙醇存在的情况下，前列腺素的加入稳定了黏液糖蛋白的合成和分泌。水浸应激对大鼠胃黏膜粘液糖蛋白合成的影响。用[^3H]-棕榈酸和[^<14>C]- n -乙酰半乳糖胺孵育水浸应激大鼠胃粘膜细胞。用冷乙醇沉淀胃多体释放的肽基trna，测定其含量。与对照大鼠相比，应激大鼠中分离的肽基trna减少了70%。从肽基trna中回收的肽显示应激大鼠[3H]-棕榈酸和[^<14>C]- n -乙酰半乳糖胺掺入量比正常对照组减少30-50%。由此可见，应激对胃粘膜核糖体中多肽的翻译、酰化和糖基化均有显著影响。少

Using gastric mucous cells which are involved exclusively in the synthesis of secretory O-glycosidic glycoprotein (mucin), the relationships between protein core synthesis and its acylation with fatty acids, O-glycosylation with N-acetylgalactosamine were investigated Labeling of the cells with[^3H]-proline, [^3H]-palmitic acid, [^<14>C]-galactosamine followed by isolation of peptidy -tRNA and release of nascent peptides indicated that the nascent peptide were already glycosylated and acylated in the ribosome of the rat gastric mucous cell.1. Prevention of alcohol-induced gastric mucosal injury by prostaglandin E-1 Effects of ethanol and prostaglandin on the glycoprotein synthesis in the gastric mucus cells have been evaluated. The rat gastric mucosal cells were subjected to a short-term tissue culture in the presence of ehtanol and prostaglandin El using[^3H]-proline, [^3H]-Palmitic acid, [^<14>C]-galactosamine. Low concentration of ehtanol (0.05-0.1M) stimulated the glycoprotein synt … More hesis, but higher concentration of ehtanol (0.5-1.5M) caused a marked reduction in the glycoprotein synthesis. Addition of prostaglandin resulted in the stabilization of the synthesis and secretion of the mucucs glycoprotein in the presence of ethanol.2. lnfluence of water-immersion stress on synthesis of mucus glycoprotein in rat gastric mucosa.Gastric raucous cells of rats subjected to water immersion stress were incubated with[^3H]-palmitic acid and[^<14>C]-N-acetylgalactosamine. The peptdyl-tRNA released by gastric polysomes was precipitated with cold ethanol and then the content was determined. A 70% reduction in the peptidyltRNA isolated was observed in the stress rats, as compared with in control rat. The peptide recoverd from the peptidyl-tRNA showed 30-50% less[3H]-Palmitic acid and[^<14>C]- N-acetylgalactosamine incorporation in the stressed rats than in normal control. It was thus suggested that translation, acylation and glycosylation of the peptides in the ribosomes of the gastric mucosa were remarkably affected by the stress. Less