大鼠肾髓质中生长激素释放激素结合位点的特性研究

Characterization of a growth hormone-releasing hormone binding site in the rat renal medulla.

作者信息

Boulanger Luce, Girard Nathalie, Strecko Julie, Gaudreau Pierrette

机构信息

Laboratory of Neuroendocrinology of Aging, Department of Medicine, CHUM Research Center, Notre-Dame Hospital, University of Montreal, 1560 East Sherbrooke Street, Que., H2L 4M1, Montreal, Canada.

出版信息

Peptides. 2002 Jun;23(6):1187-94. doi: 10.1016/s0196-9781(02)00029-3.

DOI:10.1016/s0196-9781(02)00029-3

PMID:12126750

Abstract

Receptor binding analysis was performed in the renal medulla from 2-month-old rats, an extrapituitary tissue containing the highest level of GHRH receptor mRNA. At 4 degrees C, in the presence of a cocktail of protease inhibitors, binding of [125I-Tyr(10)]hGHRH (1-44)NH(2) to medullary homogenates was specific, time-dependent, reversible and saturable (K(d): 28 nM; B(max): 30 fmol/mgprot.). In these experimental conditions, no change of binding parameters could be detected in the course of aging. The structure-affinity profile was different in the two tissues and chemical cross-linking revealed the presence of 65-, 55- and 38-kDa 125I-GHRH-labeled complexes in the renal medulla compared to 65-, 47- and 28-kDa radioactive complexes in the anterior pituitary. It is suggested that GHRH binding sites, and possibly the receptor, may be different in the two tissues.

摘要

在2月龄大鼠的肾髓质中进行了受体结合分析，肾髓质是一种垂体外组织，其生长激素释放激素（GHRH）受体mRNA水平最高。在4℃下，在蛋白酶抑制剂混合物存在的情况下，[125I-酪氨酸（10）]人GHRH（1-44）NH2与髓质匀浆的结合具有特异性、时间依赖性、可逆性和饱和性（解离常数K(d)：28 nM；最大结合容量B(max)：30 fmol/mg蛋白）。在这些实验条件下，衰老过程中未检测到结合参数的变化。两种组织中的结构-亲和力图谱不同，化学交联显示肾髓质中存在65 kDa、55 kDa和38 kDa的125I-GHRH标记复合物，而垂体前叶中存在65 kDa、47 kDa和28 kDa的放射性复合物。提示两种组织中的GHRH结合位点以及可能的受体可能不同。