Lefebvre H, Contesse V, Delarue C, Feuilloley M, Hery F, Grise P, Raynaud G, Verhofstad A A, Wolf L M, Vaudry H
European Institute for Peptide Research, CNRS URA 650, UA INSERM, University of Rouen, France.
Neuroscience. 1992;47(4):999-1007. doi: 10.1016/0306-4522(92)90047-6.
The occurrence of serotonin in the human adrenal gland was demonstrated both by immuno-histochemical and biochemical approaches. Using specific polyclonal antibodies to serotonin, the presence of numerous immunoreactive cells was revealed by means of the peroxidase-antiperoxidase technique. These cells exhibited the morphological characteristics of mast cells. Combination of high performance liquid chromatography and electrochemical detection showed the presence of substantial amounts of both serotonin and its metabolite 5-hydroxyindolacetic acid in adrenocortical extracts. The role of serotonin in the regulation of steroidogenesis from human adrenocortical slices was studied in vitro using a perifusion system technique coupled to a specific radioimmunoassay for cortisol. Graded doses of serotonin (from 10(-8) M to 3 x 10(-7) M) increased cortisol production in a dose-dependent manner. Prolonged exposure of adrenal fragments to serotonin (10(-7) M) induced a biphasic response, i.e. a rapid and transient increase in cortisol secretion followed by a plateau phase, suggesting the existence of a desensitization phenomenon. The stimulatory effect of serotonin (10(-7) M) was not altered during infusion of the serotonin1 and/or serotonin2 receptor antagonists methysergide (10(-6) M) and ketanserin (10(-6) M), respectively. In contrast, ICS 205 930 (10(-6) M), a non-selective serotonin3/serotonin4 antagonist, totally abolished the response of adrenal slices to serotonin (10(-7) M). The benzamide derivative zacopride, considered as a serotonin4 agonist, induced a robust stimulation of cortisol secretion. In addition, the corticotropic effects of serotonin (10(-7) M) and zacopride (10(-6) M) were not additive. Incubation of adrenocortical fragments with zacopride (10(-6) M) or serotonin (10(-6) M) caused a significant increase in cAMP formation. Taken together, these data suggest that serotonin, locally released by intra-adrenal mast-like cells, may act as a paracrine factor to stimulate cortisol secretion in man. Our results also indicate that serotonin-induced corticosteroid production is mediated through activation of a serotonin4 receptor subtype positively coupled to adenylate cyclase.
通过免疫组织化学和生化方法均证实了人肾上腺中5-羟色胺的存在。使用针对5-羟色胺的特异性多克隆抗体，借助过氧化物酶-抗过氧化物酶技术揭示了大量免疫反应性细胞的存在。这些细胞表现出肥大细胞的形态特征。高效液相色谱法与电化学检测相结合表明，肾上腺皮质提取物中存在大量的5-羟色胺及其代谢产物5-羟吲哚乙酸。使用与皮质醇特异性放射免疫测定相结合的灌流系统技术，在体外研究了5-羟色胺在人肾上腺皮质切片类固醇生成调节中的作用。不同剂量的5-羟色胺（从10^(-8) M到3×10^(-7) M）以剂量依赖性方式增加皮质醇的产生。肾上腺碎片长时间暴露于5-羟色胺（10^(-7) M）会诱导双相反应，即皮质醇分泌迅速短暂增加，随后进入平台期，提示存在脱敏现象。在分别注入5-羟色胺1和/或5-羟色胺2受体拮抗剂麦角新碱（10^(-6) M）和酮色林（10^(-6) M）期间，5-羟色胺（10^(-7) M）的刺激作用未改变。相反，非选择性5-羟色胺3/5-羟色胺4拮抗剂ICS 205 930（10^(-6) M）完全消除了肾上腺切片对5-羟色胺（10^(-7) M）的反应。被认为是5-羟色胺4激动剂的苯甲酰胺衍生物扎考必利可强烈刺激皮质醇分泌。此外，5-羟色胺（10^(-7) M）和扎考必利（10^(-6) M）的促肾上腺皮质激素作用并非相加。用扎考必利（10^(-6) M）或5-羟色胺（10^(-6) M）孵育肾上腺皮质碎片会导致cAMP形成显著增加。综上所述，这些数据表明，肾上腺内类似肥大细胞局部释放的5-羟色胺可能作为旁分泌因子刺激人体皮质醇分泌。我们的结果还表明，5-羟色胺诱导的皮质类固醇生成是通过与腺苷酸环化酶正偶联的5-羟色胺4受体亚型的激活介导的。
