Belo P S, Romsos D R, Leveille G A
J Nutr. 1977 Mar;107(3):397-403. doi: 10.1093/jn/107.3.397.
Four diets containing 0 to 62% of energy from carbohydrate and 24% to 48% of energy from protein were fed to young dogs. The influence of these diets on the turnover of [U-14C]-L-lactate, [U-14C]-L-alanine and [U-14C]-L-serine and on the incorporation of these gluconeogenic precursors into plasma glucose of the dog was established. Blood lactate levels were lowered when high-protein diets were fed but were not influenced by the level of carbohydrate in the diet or by a 48-hour fast. Plasma alanine and serine levels were elevated in dogs fed the high-protein diets and were lowered by a 48-hour fast. Turnover of lactate was increased in dogs fed high-carbohydrate diets whereas turnover of alanine and serine was increased in dogs fed the high-protein diets. Following a 48-hour fast, 14C-lactate conversion to plasma glucose was lower in dogs fed the high-protein diets than in dogs fed the lower protein diets whereas 14C-alanine and 14C-serine conversion to plasma glucose was increased in dogs fed the high-protein. Thus, the diet consumed altered the relative importance of these gluconeogenic precursors to the maintenance of plasma glucose.
给幼犬喂食四种日粮，碳水化合物提供的能量占比为0%至62%，蛋白质提供的能量占比为24%至48%。研究了这些日粮对[U-14C]-L-乳酸、[U-14C]-L-丙氨酸和[U-14C]-L-丝氨酸周转的影响，以及这些糖异生前体掺入犬血浆葡萄糖的情况。喂食高蛋白日粮时，血乳酸水平降低，但日粮中的碳水化合物水平或48小时禁食对其没有影响。喂食高蛋白日粮的犬血浆丙氨酸和丝氨酸水平升高，48小时禁食会使其降低。喂食高碳水化合物日粮的犬乳酸周转增加，而喂食高蛋白日粮的犬丙氨酸和丝氨酸周转增加。48小时禁食后，喂食高蛋白日粮的犬中14C-乳酸转化为血浆葡萄糖的比例低于喂食低蛋白日粮的犬，而喂食高蛋白日粮的犬中14C-丙氨酸和14C-丝氨酸转化为血浆葡萄糖的比例增加。因此，所摄入的日粮改变了这些糖异生前体对维持血浆葡萄糖的相对重要性。
