Palou A, Remesar X, Arola L, Herrera E, Alemany M
Horm Metab Res. 1981 Jun;13(6):326-30. doi: 10.1055/s-2007-1019258.
The effects of food deprivation for up to 24 hours on plasma metabolic parameters in the rat have been studied. Liver dry weight and glycogen content dropped significantly from 3 hours of food deprivation onwards. Total muscle glycogen supplied about as much glycosyl residues or precursors as did the liver. Plasma glucose, urea, lactate and total and essential amino acids decreased significantly from 3 hours of fasting onwards. Glycerol, free significantly from 3 hours of fasting onwards. Glycerol, free fatty acids, beta-hydroxybutyrate and acetoacetate showed significant increases with fasting. Alanine, serine, arginine, threonine, aspartate plus asparagine and proline showed significant decreases with fasting. Several other amino acids showed almost no change with fasting. Lysine, leucine plus isoleucine and taurine showed biphasic changes in their concentrations with a minimum at 6 hours and a transient recovery at 12 hours of fasting Essential amino acids decreased more than the non essential ones. With fasting there is a shift in ammonia disposal with lower urea concentrations as nitrogen is better conserved. The results seem to suggest that there is a constant release of substrates, through liver and peripheral tissue proteolysis, that is counteracted by differential utilization of amino acids during fasting.
研究了长达24小时的食物剥夺对大鼠血浆代谢参数的影响。从食物剥夺3小时起，肝脏干重和糖原含量显著下降。总的肌肉糖原提供的糖基残基或前体与肝脏提供的大致相同。从禁食3小时起，血浆葡萄糖、尿素、乳酸以及总氨基酸和必需氨基酸显著减少。甘油从禁食3小时起显著增加。甘油、游离脂肪酸、β-羟基丁酸和乙酰乙酸随着禁食而显著增加。丙氨酸、丝氨酸、精氨酸、苏氨酸、天冬氨酸加天冬酰胺和脯氨酸随着禁食而显著减少。其他几种氨基酸随着禁食几乎没有变化。赖氨酸、亮氨酸加异亮氨酸和牛磺酸的浓度呈双相变化，在禁食6小时时最低，在禁食12小时时有短暂恢复。必需氨基酸的减少比非必需氨基酸更多。随着禁食，氨的处理方式发生转变，由于氮得到更好的保留，尿素浓度降低。结果似乎表明，通过肝脏和外周组织的蛋白水解作用，底物持续释放，而在禁食期间氨基酸的差异利用可抵消这种释放。
