肝细胞的异质性：葡萄糖和酮体在大鼠肝脏的代谢

用大鼠肝脏门静脉或肝静脉周围的肝细胞来研究葡萄糖和酮体生成的区域分布。肝细胞通过毛地黄皂苷－胶原酶灌流技术分离。门静脉周围肝细胞的γ谷氨酰转肽酶的活性比肝静脉周围肝细胞高２．４倍；而谷氨酰胺合成酶的活性则相反，肝静脉周围肝细胞高出５６倍。门静脉周围肝细胞的内源性葡萄糖合成比肝静脉周围肝细胞高１．５７倍。给予刺激葡萄糖异生的底物，门静脉周围肝细胞的葡萄糖合成则增加１．７－２．１倍。肝静脉周围肝细胞的内源性酮体生成比门静脉周围肝细胞高１．３倍。给予能明显刺激酮体生成的辛酸盐，肝静脉周围肝细胞的酮体生成仅略为增加。我们的结果证实，在基础和刺激的条件下，葡萄糖的异生在门静脉周围肝细胞中优先，而酮体生成仅在肝静脉周围肝细胞占微弱的优势。

Hepatocellular Heterogeneity:Glucose and Ketone Body Metabolism in Rat Liver

Zonation of ketone body and glucose metabolism was studied in hepatocyte preparations enriched with cells from the periportal or the perivenous zone of the liver lobule.Hepatocytes were isolated by the digitonin-collagenase perfusion technique. γ-Glutamyltransferase activity was 2. 4times higher in periportal cells than that in perivenous hepatocytes, while glutamine synthetase was 56-times higher in perivenous than in periportal cells.Endogenous glucose synthesis was 1.57 fold higher in periportal zone. Stimulation of gluconeogenesis by administration of gluconeogenic substrates resulted in 1.7-2.1-times higher rates of glucose synthesis in the periportal cells than in perivenous hepatocytes. Endogenous ketogenesis was 1.3-times higher in the perivenous zone than in periportal hepatocytes. Administration of octanoate to stimulate ketogenesis showed only slight increase of ketone body in perivenous zone. Our results demonstrate that gluconeogenesis has a preferential periportal location both at basal and under stimulated conditions, while ketone body metabolism shows only a minor acinar distribution preference in perivenous zone.