Glucocorticoidal regulation of pituitary vasopressin content in rats.
Although glucocorticoids are known to attenuate vasopressin (AVP) secretion, it is still controversial whether glucocorticoids act on the hypothalamo-neurohypophysial system. We report here glucocorticoidal regulation of pituitary AVP content, which is a specific indicator for the system. The hypothalamic AVP mRNA content and the pituitary AVP content were measured in rats given dexamethasone (2 mg/kg, 2 times over the course of 5 d) or the glucocorticoid receptor antagonist RU-38486 (20 mg/kg, 3 times over the course of 3 d) during euhydration or dehydration. In dexamethasone-treated rats, both the hypothalamic AVP mRNA content and pituitary AVP content decreased after dehydration. In contrast, in the RU-38486 group the hypothalamic AVP mRNA content and pituitary AVP content increased in both euhydrated and dehydrated rats. These results suggest that glucocorticoids may act on hypothalamo-neurohypophysial vasopressinergic system and attenuate its activity under both basal and dehydrated states.
Shoji
M
M
Department of Laboratory Medicine, Hirosaki University School of Medicine, Japan.
Kimura
T
T
Ota
K
K
Ohta
M
M
Mori
T
T
Sahata
T
T
Yasujima
M
M
D000199:Actins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001127:Arginine Vasopressin / Q000235:genetics / Q000378:metabolism*; D015152:Blotting, Northern; D003907:Dexamethasone / Q000494:pharmacology*; D005938:Glucocorticoids / Q000494:pharmacology*; D006727:Hormone Antagonists / Q000494:pharmacology; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D008297:Male; D015735:Mifepristone / Q000494:pharmacology; D010902:Pituitary Gland / Q000187:drug effects* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D011965:Receptors, Glucocorticoid / Q000037:antagonists & inhibitors
D000199:Actins; D005938:Glucocorticoids; D006727:Hormone Antagonists; D012333:RNA, Messenger; D011965:Receptors, Glucocorticoid; D001127:Arginine Vasopressin; D015735:Mifepristone; D003907:Dexamethasone