Bennett H P, McMartin C
J Endocrinol. 1979 Jul;82(1):33-42. doi: 10.1677/joe.0.0820033.
The distribution and degradation of corticotrophin-(1--24)-tetracosapeptide specifically labelled with tritium at Tyr2, Phe7 or Tyr23 and [D-Ser1, Lys17, Lys18]-corticotrophin-(1--18)-octadecapeptide amide labelled at Tyr2 were studied at various times after intravenous injection into rats. By characterizing the radioactivity in plasma and various tissues, an overall picture of the metabolic handling of the two peptides emerged. The peptides left the circulation rapidly, entering mainly muscle and skin where they were extensively degraded. The D-Ser1-containing analogue was less rapidly degraded and intact peptide persisted in muscle and skin for up to 1 h. This peptide probably returned to the circulation giving rise to the sustained plasma levels observed after injection of the D-Ser1-substituted octadecapeptide but not after injection of the tetracosapeptide. Although initially the kidneys did not clear such large amounts of peptide as did muscle and skin they played an important role by continuously and, on the basis of existing evidence, irreversibly clearing the peptides and peptide fragments from the circulation and degrading them.
在给大鼠静脉注射后，于不同时间研究了分别在Tyr2、Phe7或Tyr23处用氚特异性标记的促肾上腺皮质激素-（1-24）-二十四肽以及在Tyr2处标记的[D-丝氨酸1，赖氨酸17，赖氨酸18]-促肾上腺皮质激素-（1-18）-十八肽酰胺的分布和降解情况。通过对血浆和各种组织中的放射性进行表征，得出了这两种肽代谢处理的总体情况。这些肽迅速离开循环系统，主要进入肌肉和皮肤，并在那里被大量降解。含D-丝氨酸1的类似物降解较慢，完整的肽在肌肉和皮肤中可持续存在长达1小时。这种肽可能返回循环系统，导致在注射D-丝氨酸1取代的十八肽后观察到持续的血浆水平，但在注射二十四肽后未观察到。尽管最初肾脏不像肌肉和皮肤那样清除大量的肽，但它们通过持续且根据现有证据不可逆地从循环系统中清除肽和肽片段并使其降解，发挥了重要作用。
