Effects of angiotensin II on release of CRH and AVP from hypothalamus during acute hypoxia.
OBJECTIVE
To investigate the effects of angiotensin II (Ang II) on corticotropin-releasing hormone (CRH) and argipressin (AVP) release from median eminence (ME) of hypothalamus during acute hypoxia in rats.


METHODS
Simulated hypoxia was performed in a hypobaric chamber. CRH and AVP were determined by radioimmunoassay (RIA). Plasma corticosterone concentration was measured by fluorometry.


RESULTS
Ang II did not influence CRH release induced by hypoxia [CRH in group pretreated with Ang II (16 +/- 8) ng/ME vs control (15 +/- 4) ng/ME, both exposed to hypoxia with simulated altitude 7 km (8.2% O2)]. Ang II enhanced AVP release, from (5.7 +/- 1.6) ng/ME in control decreasing to (2.6 +/- 1.2) ng/ME (P < 0.05), meanwhile plasma corticosterone concentration was also increased markedly, from (356 +/- 58) in control to (536 +/- 134) micrograms/L plasma (P < 0.05), which was partly abolished by administration of AVP antiserum.


CONCLUSIONS
Ang II might stimulate hypothalamo-pituitary-adrenal axis (HPA) through activating AVP but not CRH release during acute hypoxia.
Wu
Y
Y
Division of Neurobiology and Physiology, College of Sciences (Yuquan Campus), Zhejiang University, Hangzhou 310027, China.
Du
J Z
JZ
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism*; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism*; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D008473:Median Eminence / Q000378:metabolism*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar
D000804:Angiotensin II; D001127:Arginine Vasopressin; D003346:Corticotropin-Releasing Hormone