Is a hypertensinogenic factor present in the kidney of hypertensive dahl rats?
1. Early studies suggest that hypertension in Dahl salt-sensitive (S) rats is related to an uncommon humoral factor that may be released from the kidney. 2. To investigate whether the kidney releases a hypertensinogenic factor for developing salt-induced hypertension in S rats, we examined a pressor effect, or vascular contractive activity of a kidney extract from S rats using a conscious recipient rat or an isolated aortic ring. 3. Donor S and Dahl salt-resistant (R) rats were fed a 0.4 or 8% NaCl diet for 4 weeks and were then used to provide four kinds of kidney extracts (S-0.4%, S-8%, R-0.4%, R-8%). The systolic arterial pressure (SAP) was significantly increased in donor S rats fed an 8% NaCl diet compared with other donor rat groups. 4. All four types of kidney extract increased mean arterial pressure (MAP) in a recipient rat fed a 0.4% NaCl diet. However, the increase in MAP observed following infusion of the S-8% extract was the least of all groups. An angiotensin AT1 receptor antagonist, CV-11974, abolished any pressor effect of all kidney extracts. In an in vitro experiment, all four types of kidney extract evoked contractile responses in aortic rings, but elicited no significant difference in aortic ring contractile force. 5. These results suggest that the kidney of S rats may not release an active hypertensinogenic factor that would cause salt-induced hypertension.
Department of Physiology, Kagawa Medical University, Miki, Japan.
M S
MS
Zhou
Y
Y
Nishida
Q H
QH
Chen
H
H
Murakami
H
H
Hosomi
H
H
Kosaka
D057911:Angiotensin Receptor Antagonists; D000808:Angiotensinogen / Q000032:analysis*; D000818:Animals; D001011:Aorta / Q000187:drug effects; D001562:Benzimidazoles / Q000494:pharmacology; D001713:Biphenyl Compounds; D001794:Blood Pressure / Q000187:drug effects; D006973:Hypertension / Q000209:etiology / Q000378:metabolism*; D066298:In Vitro Techniques; D007668:Kidney / Q000378:metabolism*; D009119:Muscle Contraction / Q000187:drug effects; D051381:Rats; D020303:Rats, Inbred Dahl; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D012965:Sodium Chloride / Q000008:administration & dosage; D013777:Tetrazoles / Q000494:pharmacology; D014020:Tissue Extracts / Q000037:antagonists & inhibitors / Q000494:pharmacology
D057911:Angiotensin Receptor Antagonists; D001562:Benzimidazoles; D001713:Biphenyl Compounds; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D013777:Tetrazoles; D014020:Tissue Extracts; D000808:Angiotensinogen; D012965:Sodium Chloride; C081643:candesartan