Pocius P A, Clark J H, Baumrucker C R
J Dairy Sci. 1981 Jul;64(7):1551-4. doi: 10.3168/jds.S0022-0302(81)82724-5.
Glutathione (gamma-glutamyl-cysteinyl-glycine) concentrations of plasma and whole blood were measured for lactating Holstein cows. Samples were taken from both the internal iliac artery and mammary vein to calculate arteriovenous differences across the mammary gland. Glutathione in plasma was extremely low, the there was no significant arteriovenous difference of this tripeptide across the mammary gland. In contrast, glutathione in whole blood was 200-fold greater than in plasma and showed a significant arteriovenous difference across the mammary gland. In vivo studies have shown that when arteriovenous differences of free amino acids in plasma are quantitated, there appears to be a shortage of cysteine for synthesis of milk protein. Using estimated blood flow and arteriovenous differences, we calculated that mammary gland uptake of glutathione from whole blood is more than enough to account for the amount of cysteine secreted in milk. Implications regarding availability to the mammary gland of glutathione from whole blood are discussed.
对泌乳期荷斯坦奶牛的血浆和全血中的谷胱甘肽（γ-谷氨酰-半胱氨酰-甘氨酸）浓度进行了测定。从髂内动脉和乳腺静脉采集样本，以计算乳腺的动静脉差异。血浆中的谷胱甘肽极低，该三肽在乳腺中没有显著的动静脉差异。相比之下，全血中的谷胱甘肽比血浆中的高200倍，并且在乳腺中显示出显著的动静脉差异。体内研究表明，当定量血浆中游离氨基酸的动静脉差异时，似乎缺乏用于合成乳蛋白的半胱氨酸。利用估计的血流量和动静脉差异，我们计算出全血中乳腺对谷胱甘肽的摄取量足以满足乳汁中分泌的半胱氨酸量。讨论了全血中谷胱甘肽对乳腺可用性的影响。
