Knight C D, Dibner J J
J Nutr. 1984 Nov;114(11):2179-86. doi: 10.1093/jn/114.11.2179.
The absorption of [1-14C]2-hydroxy-4-(methylthio)butanoic acid (HMB) and L-methionine (L-Met) was evaluated in the broiler chick. Methods included in vitro intestinal tissue uptake and appearance in the plasma from ligated intestinal segments in situ, and from crop intubations. Intestinal uptake of L-Met was partially inhibited with 2,4-dinitrophenol, while HMB uptake was unaffected. The uptake of L-Met conformed to Michaelis-Menten kinetics except that no plateau was reached. This indicated that L-Met absorption may be accomplished by both concentration and energy-dependent processes. The in vitro uptake of HMB in relation to concentration was linear indicating that its absorption was concentration dependent. Absorption of HMB and L-Met after crop intubation indicated higher plasma concentrations of HMB than of L-Met, particularly at higher doses. Both compounds were absorbed at similar rates at concentrations 50-100 times below physiological concentrations and absorption rates were different at different small intestinal locations. These results indicate that the ability to use HMB as a source of methionine would not be limited by absorption.
在肉鸡中评估了[1-¹⁴C]2-羟基-4-(甲硫基)丁酸(HMB)和L-蛋氨酸(L-Met)的吸收情况。方法包括体外肠组织摄取以及通过原位结扎肠段和嗉囊插管后血浆中的出现情况。L-Met的肠摄取被2,4-二硝基苯酚部分抑制，而HMB的摄取不受影响。L-Met的摄取符合米氏动力学，只是未达到平台期。这表明L-Met的吸收可能通过浓度依赖性和能量依赖性过程来完成。HMB的体外摄取与浓度呈线性关系，表明其吸收是浓度依赖性的。嗉囊插管后HMB和L-Met的吸收表明，HMB的血浆浓度高于L-Met，尤其是在高剂量时。在低于生理浓度50-100倍的浓度下，两种化合物的吸收速率相似，且在不同小肠部位的吸收速率不同。这些结果表明，将HMB用作蛋氨酸来源的能力不会受到吸收的限制。
