Vasopressin response to haemorrhage in rats: effect of hypoxia and water restriction.
1. The aim of the present study was to determine the effect of water restriction and/or hypoxia on the vasopressin response to haemorrhage in conscious rats. 2. Male, Long-Evans rats (n = 39) were prepared with chronically indwelling femoral artery and vein catheters and exposed to 24 h of one of the following: normoxia with ad lib drinking water (N + W); normoxia with water restriction (N - W); hypoxia with ad lib drinking water (H + W); and hypoxia with water restriction (H - W). At the end of 24 h, a 15 mL/kg arterial haemorrhage was performed. 3. Water restricted rats had elevated pre-haemorrhage vasopressin levels. Haemorrhage induced an increase in vasopressin in all groups. Water restriction (N - W) or hypoxia (H + W) each augmented the vasopressin response to haemorrhage. However, the combination of hypoxia and water restriction (H - W) failed to augment the vasopressin response to haemorrhage as compared to normoxic, water replete (N + W) rats. 4. Hypoxia or water restriction per se augment the vasopressin response to haemorrhage. This augmented vasopressin response to haemorrhage is not maintained when hypoxia and water restriction are combined.
Raff
H
H
Endocrine Research Laboratory, St Luke's Medical Center, Milwaukee, Wisconsin 53215.
Rossing
M H
MH
Doepker
S K
SK
Griffen
S C
SC
Jankowski
B M
BM
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D006470:Hemorrhage / Q000097:blood / Q000503:physiopathology*; D000860:Hypoxia / Q000097:blood / Q000503:physiopathology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014667:Vasopressins / Q000097:blood / Q000378:metabolism / Q000494:pharmacology*; D014868:Water Deprivation / Q000502:physiology*
D014667:Vasopressins