Rönnemaa T, Vihersaari T, Ranta H
Scand J Clin Lab Invest. 1977 Jun;37(4):351-6. doi: 10.3109/00365517709092641.
Earlier we have found that 35,000 g supernatants of liver homogenates from both normal and hypercholesterolaemic rats stimulate the synthesis of collagen by freshly isolated fibroblasts. Supernatants from the fatty livers of hypercholesterolaemic rats showed greater stimulation. In the present study we fractionated the 35,000 g supernatants using gel filtration, ion-exchange chromatography, paper electrophoresis and paper chromatography. One of the stimulating factors turned out to be glutamine. However, the concentration of glutamine was the same in normal and fatty livers suggesting that glutamine is not responsible for the greater stimulating activity found in the 35,000 g supernatants from fatty livers. Authentic glutamine increased the synthesis of collagen by 40% at a concentration of 40 mumol/l but inhibited it 80% at 4 mmol/l, which is widely used in cell culture media. There, the concentration of glutamine should be controlled carefully in tests for collagen synthesis in vitro.
早些时候我们发现，正常大鼠和高胆固醇血症大鼠肝脏匀浆的35,000g上清液可刺激新鲜分离的成纤维细胞合成胶原蛋白。高胆固醇血症大鼠脂肪肝的上清液显示出更强的刺激作用。在本研究中，我们使用凝胶过滤、离子交换色谱、纸电泳和纸色谱对35,000g上清液进行了分级分离。其中一种刺激因子被证明是谷氨酰胺。然而，正常肝脏和脂肪肝中谷氨酰胺的浓度相同，这表明谷氨酰胺并非导致脂肪肝35,000g上清液中更强刺激活性的原因。纯度经鉴定的谷氨酰胺在浓度为40μmol/L时可使胶原蛋白合成增加40%，但在4mmol/L时则抑制80%，4mmol/L这一浓度在细胞培养基中广泛使用。因此，在体外胶原蛋白合成试验中应仔细控制谷氨酰胺的浓度。
