Dores R M, Meza J C, Schenk L M, Carr J A, Norris D O
Department of Biological Sciences, University of Denver, Colorado 80208.
Endocrinology. 1989 Feb;124(2):1007-16. doi: 10.1210/endo-124-2-1007.
Immunohistochemical analysis revealed the colocalization of ACTH-related immunoreactive forms and alpha-MSH-related immunoreactive forms in corticotropic cells of the anterior pituitary of larval Ambystoma tigrinum. Subsequent analysis of acid extracts of anterior pituitaries obtained from larval, neotene, and postmetamorphic adults indicated that the molar ratio of ACTH(1-39) to alpha-MSH was, respectively, 2.5:1, 1:1.5, and 1:1.3. However, in sexually mature adults the molar ratio of ACTH(1-39) to alpha-MSH was 8:1. These results indicate that before and immediately after metamorphosis, both ACTH(1-39) and alpha-MSH are major end products of corticotropic cells in this species. As postmetamorphic animals reach sexual maturity, ACTH(1-39) is a major end product of corticotropic cells and only trace amounts of alpha-MSH are produced. Thus in A. tigrinum the proteolytic processing of ACTH in corticotropic cells is developmentally regulated. The alpha-MSH-related peptide produced by the corticotropic cells appears to be an ACTH(1-13)amide-like form.
免疫组织化学分析显示，在虎纹钝口螈幼体垂体前叶的促肾上腺皮质激素细胞中，促肾上腺皮质激素相关免疫反应形式与α-促黑素相关免疫反应形式共定位。随后对取自幼体、幼态持续期和变态后成体的垂体前叶酸性提取物的分析表明，促肾上腺皮质激素（1-39）与α-促黑素的摩尔比分别为2.5:1、1:1.5和1:1.3。然而，在性成熟的成体中，促肾上腺皮质激素（1-39）与α-促黑素的摩尔比为8:1。这些结果表明，在变态前和变态后不久，促肾上腺皮质激素（1-39）和α-促黑素都是该物种促肾上腺皮质激素细胞的主要终产物。随着变态后的动物达到性成熟，促肾上腺皮质激素（1-39）是促肾上腺皮质激素细胞的主要终产物，仅产生微量的α-促黑素。因此，在虎纹钝口螈中，促肾上腺皮质激素细胞中促肾上腺皮质激素的蛋白水解加工受到发育调控。促肾上腺皮质激素细胞产生的α-促黑素相关肽似乎是一种促肾上腺皮质激素（1-13）酰胺样形式。
