泌乳山羊乳腺摄取血液甘油三酯方式的研究。标记甘油、脂肪酸和甘油三酯在乳脂肪和乳腺淋巴中的摄取与掺入。

Studies on the mode of uptake of blood triglycerides by the mammary gland of the lactating goat. The uptake and incorporation into milk fat and mammary lymph of labelled glycerol, fatty acids and triglycerides.

作者信息

West C E, Bickerstafee R, Annison E F, Linzell J L

出版信息

Biochem J. 1972 Feb;126(3):477-90. doi: 10.1042/bj1260477.

DOI:10.1042/bj1260477

PMID:4672665

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1178403/

Abstract

The mode of uptake of the precursors of milk fat by the mammary gland of the lactating goat has been examined by infusing radioactive fatty acids, glucerol or doubly labelled triglycerides into the mammary artery or jugular vein of animals surgically prepared to permit samples of arterial and venous blood to be withdrawn without disturbance to the animal. 2. Acetate was taken up by the mammary gland and incorporated into milk fat. The decrease in the specific radioactivity of blood acetate across the gland was evidence of acetate production, but there was no significant release of labelled lipid from the mammary gland. 3. When labelled long-chain fatty acids or glycerol were infused into the lactating goat, there was extensive transfer of radioactivity into milk in spite of the absence of net uptake of substrate by the mammary gland. The decrease in the specific radioactivity of each substrate across the mammary gland, however, showed that both fatty acids and glycerol were simultaneously taken up and released by mammary tissue. 4. The infusion of chylomicra and triglyceride emulsions labelled with (3)H and (14)C revealed that both glycerol and fatty acids were released during triglyceride uptake by mammary tissue. Changes in the (3)H/(14)C ratio during the transfer of triglyceride from blood into milk showed that at least 80% of the triglyceride was hydrolysed during uptake, but the potential re-utilization of both products of hydrolysis for triglyceride synthesis in mammary tissue implied that only a minimum value could be obtained from the change in the ratio. 5. The time-course of the transfer of (3)H and (14)C into milk and lymph were closely similar after the infusion of [2-(3)H]glycerol tri[1-(14)C]oleate or of a mixture of [2-(3)H]glycerol and [1-(14)C]oleate. 6. The results were consistent with the hypothesis that plasma triglycerides are extensively or completely hydrolysed during mammary uptake.

摘要

通过将放射性脂肪酸、甘油或双标记甘油三酯注入经手术准备的泌乳山羊的乳腺动脉或颈静脉，以研究泌乳山羊乳腺摄取乳脂肪前体的方式，这样可以在不干扰动物的情况下采集动脉血和静脉血样本。2. 乙酸盐被乳腺摄取并掺入乳脂肪中。乳腺中血乙酸盐比放射性的降低证明了乙酸盐的生成，但乳腺中没有明显的标记脂质释放。3. 当将标记的长链脂肪酸或甘油注入泌乳山羊体内时，尽管乳腺没有净摄取底物，但放射性仍大量转移到乳汁中。然而，每种底物在乳腺中的比放射性降低表明，脂肪酸和甘油同时被乳腺组织摄取和释放。4. 注入用³H和¹⁴C标记的乳糜微粒和甘油三酯乳剂表明，在乳腺组织摄取甘油三酯期间，甘油和脂肪酸都会释放出来。甘油三酯从血液转移到乳汁过程中³H/¹⁴C比值的变化表明，摄取过程中至少80%的甘油三酯被水解，但水解产物在乳腺组织中用于甘油三酯合成的潜在再利用意味着只能从该比值变化中获得最小值。5. 注入[2-³H]甘油三[1-¹⁴C]油酸酯或[2-³H]甘油和[1-¹⁴C]油酸酯混合物后，³H和¹⁴C转移到乳汁和淋巴中的时间进程非常相似。6. 这些结果与以下假设一致，即血浆甘油三酯在乳腺摄取过程中被广泛或完全水解。