Emmison N, Agius L, Zammit V A
Hannah Research Institute, Ayr, Scotland.
Biochem J. 1991 Feb 15;274 ( Pt 1)(Pt 1):21-6. doi: 10.1042/bj2740021.
Primary monolayer hepatocyte cultures derived from non-mated, pregnant and lactating sheep were used to investigate the interactions between the effects of growth hormone and insulin on (i) the partitioning of fatty acid metabolism between oxidation and esterification, and (ii) the rate of gluconeogenesis. In hepatocytes from lactating sheep the rates of gluconeogenesis, ketogenesis and very-low-density lipoprotein secretion were approx. 2-fold higher than in cells from non-mated or pregnant animals. There was no apparent difference in the rates of fatty acid uptake between the three groups of sheep cells. Growth hormone stimulated gluconeogenesis only in hepatocytes from non-mated sheep. It has no effect on the flux of fatty acid towards ketone body formation. Growth hormone inhibited intracellular accumulation of acylglycerol from exogenous fatty acid. Insulin alone had no such effect, but it blunted the effect of growth hormone when the two hormones were present together. The data suggest that major differences may exist between ruminants and non-ruminants in the response of liver metabolism both to lactation per se and to the effects of growth hormone and insulin.
源自未交配、怀孕和泌乳绵羊的原代单层肝细胞培养物被用于研究生长激素和胰岛素的作用之间的相互作用，这些作用包括：（i）脂肪酸代谢在氧化和酯化之间的分配，以及（ii）糖异生的速率。在泌乳绵羊的肝细胞中，糖异生、生酮和极低密度脂蛋白分泌的速率比未交配或怀孕动物的细胞中的速率高出约2倍。三组绵羊细胞之间的脂肪酸摄取速率没有明显差异。生长激素仅在未交配绵羊的肝细胞中刺激糖异生。它对脂肪酸向酮体形成的通量没有影响。生长激素抑制外源性脂肪酸的酰基甘油在细胞内的积累。单独的胰岛素没有这种作用，但当两种激素同时存在时，它会减弱生长激素的作用。数据表明，反刍动物和非反刍动物在肝脏代谢对泌乳本身以及生长激素和胰岛素作用的反应方面可能存在重大差异。
