ANTIDIURETIC-HORMONE STIMULATION OF ADENYLATE-CYCLASE IN SEMICIRCULAR CANAL EPITHELIUM

被引:1
作者
FERRARY, E [1 ]
BERNARD, C [1 ]
FRIEDLANDER, G [1 ]
STERKERS, O [1 ]
AMIEL, C [1 ]
机构
[1] UNIV ROUEN HAUTE NORMANDIE,FAC SCI,CNRS,UA 650,F-76130 MT ST AIGNAN,FRANCE
关键词
SEMICIRCULAR CANAL; VASOTOCIN; ENDOLYMPH; CYCLIC ADENOSINE MONOPHOSPHATE; ADENYLATE CYCLASE;
D O I
暂无
中图分类号
R76 [耳鼻咽喉科学];
学科分类号
100213 ;
摘要
Basal adenosine 3',5'-cyclic monophosphate (cAMP) content and the modulation of its production were studied in the frog's semicircular canal epithelium. This epithelium secretes endolymph, a K+-rich, positively polarized fluid. The basal cAMP content measured by microradioimmunoassay was 244 +/- 14.2 fmol/structure per 5 min (n = 30). This content was increased about 8 times by 10(-5) M forskolin. Vasotocin, the frog antidiuretic hormone, increased the cAMP production by factors of 1.3 and 3.3 at concentrations of 10(-8) M and 10(-7) M, respectively. This stimulatory effect of vasotocin was blunted by the addition of alpha-2-adrenergic agonists, such as 10(-8) M-10(-5) M norepinephrine, in the presence of 10(-5) M propranolol, or 10(-5) M clonidine. Prostaglandin E2 at a concentration of 10(-8) M, which did not affect the cAMP production, did not modify the response to vasotocin. Glucagon (10(-6) M), calcitonin (10(-6) M), and parathyroid hormone (10 units/ml) did not affect the cAMP content. Prostaglandin E2 (10(-7) M) and the beta-adrenergic agonist isoproterenol (10(-6) M) stimulated the cAMP production by a factor of 1.6. These results indicate that the frog semicircular canal is a target of both vasotocin and catecholamines and that catecholamines through alpha-2-receptors modulate vasotocin-induced cAMP generation. Further, this interaction might be of physiological relevance in the modulation of ion transport in this structure.
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页码:275 / 278
页数:4
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