Pocius P A, Herbein J H
J Dairy Sci. 1986 Mar;69(3):713-20. doi: 10.3168/jds.S0022-0302(86)80460-X.
Bovine growth hormone (50 IU/d) or placebo injections were administered for 11 consecutive d to Holstein cows (four per treatment) in midlactation. Growth hormone injections increased milk yield, efficiency of milk production, and concentrations of growth hormone and free fatty acids in plasma. Concentrations of beta-hydroxybutyrate and acetoacetate in whole blood and glucose in plasma were not affected by treatment. Liver biopsies were taken from both groups of cows 8 d prior to and on the last day of injection. Liver slices were used for in vitro incubations with carbon-14-labeled propionate, alanine, butyrate, and palmitate. Rates of substrate metabolism before and after placebo treatment were similar. Compared with pretreatment, however, liver slices from cows receiving growth hormone had significantly higher rates of propionate conversion to both glucose and carbon dioxide. There was also a nonsignificant increase in rate of alanine conversion to glucose and carbon dioxide. Growth hormone treatment did not change in vitro production of ketones or carbon dioxide from butyrate or palminate. Results indicate that growth hormone increases hepatic capacity for propionate metabolism and supports the concept that growth hormone partitions fatty acids for preferential use by mammary tissue.
向泌乳中期的荷斯坦奶牛（每组4头）连续11天注射牛生长激素（50国际单位/天）或安慰剂。注射生长激素可提高产奶量、产奶效率以及血浆中生长激素和游离脂肪酸的浓度。全血中β-羟基丁酸酯和乙酰乙酸酯的浓度以及血浆中葡萄糖的浓度不受处理影响。在注射前8天和注射最后一天从两组奶牛身上采集肝活检样本。肝切片用于与碳-14标记的丙酸盐、丙氨酸、丁酸盐和棕榈酸盐进行体外孵育。安慰剂处理前后底物代谢率相似。然而，与预处理相比，接受生长激素的奶牛的肝切片将丙酸盐转化为葡萄糖和二氧化碳的速率显著更高。丙氨酸转化为葡萄糖和二氧化碳的速率也有不显著的增加。生长激素处理并未改变丁酸盐或棕榈酸盐体外产生酮或二氧化碳的情况。结果表明，生长激素可提高肝脏对丙酸盐代谢的能力，并支持生长激素将脂肪酸分配给乳腺组织优先利用这一概念。
