PMID- 2537043
OWN - NLM
STAT- MEDLINE
DCOM- 19890323
LR  - 20171213
IS  - 0002-9513 (Print)
IS  - 0002-9513 (Linking)
VI  - 256
IP  - 2 Pt 2
DP  - 1989 Feb
TI  - Chronic CEI alters effect of low Na+ diet in normal and coarcted pups. II. Na+ 
      and H2O balance.
PG  - R531-40
AB  - To assess angiotensin (ANG II) dependence of evolving neonatally induced 
      coarctation hypertension (NICH) in inbred pups, we randomized sex-matched 
      littermates to high-dose converting enzyme inhibitor (CEI: MK-421, 3 mg/kg) or 
      placebo from the time of neonatal aortic banding (coarcted) vs. no banding 
      (control). During phase 1 studies over 4 mo postbanding during ad libitum Na+ 
      intake (Bagby and Fuchs, Hypertension Dallas in press). CEI failed to prevent 
      evolution of proximal blood pressure (BP) excess or to impair renal function. 
      Phase 2 studies examine, in the same pups, responses to low Na+ (LS) diet 
      superimposed on chronic CEI at 4 mo, timed to allow development of BP increase in 
      untreated NICH. The present report details metabolic handling and balances of 
      Na+, K+, and fluid for 3 days before (normal Na+ intake) and daily for 11 days 
      after initiation of LS diet, a companion paper describes BP, renin-angiotensin 
      (RA), and renal functional responses. In no case did metabolic responses of 
      coarcted pups to LS diet differ from those of controls, whether on CEI or 
      placebo, whereas responses to LS diet and to CEI reveal positive findings of 
      independent interest. LS diet induced expected renal and fecal Na+ conservation, 
      no net effect on K+ balance, and, despite unexpected free-water diuresis, mild 
      hyponatremia. Chronic CEI impaired maximal renal (but not fecal) Na+ conservation 
      during LS diet, caused exaggerated free-water diuresis but no change in fluid 
      balance, and thus, with the larger Na+ deficit, accounted for greater 
      hyponatremia. CEI caused no net effect on K+ balance. Results indicate normal 
      renal handling of fluid, Na+, and K+ in evolving NICH and provide no evidence for 
      selective intrarenal RA activation or exaggerated ANG II dependence. Findings 
      also suggest that, during LS diet, ANG II is 1) essential for maximum renal Na+ 
      conservation and normal free-water handling, and 2) not essential for fecal Na+ 
      and water conservation or for maintenance of normal water and K+ balances. 
      Results are also compatible with a CEI-induced thirst stimulation and/or osmotic 
      insensitivity and with functional vasopressin deficiency during LS diet.
FAU - Bagby, S P
AU  - Bagby SP
AD  - Department of Medicine, Portland Veterans Administration Medical Center, Oregon 
      Health Sciences University 97207.
FAU - Fuchs, E
AU  - Fuchs E
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PL  - United States
TA  - Am J Physiol
JT  - The American journal of physiology
JID - 0370511
RN  - 69PN84IO1A (Enalapril)
RN  - 9NEZ333N27 (Sodium)
RN  - RWP5GA015D (Potassium)
SB  - IM
MH  - Animals
MH  - Blood Urea Nitrogen
MH  - Body Weight
MH  - *Diet, Sodium-Restricted
MH  - Dogs
MH  - Enalapril/*pharmacology
MH  - Female
MH  - Hypertension/*physiopathology
MH  - Male
MH  - Potassium/metabolism
MH  - Reference Values
MH  - Sodium/*metabolism
MH  - *Water-Electrolyte Balance/drug effects
EDAT- 1989/02/01 00:00
MHDA- 1989/02/01 00:01
CRDT- 1989/02/01 00:00
PHST- 1989/02/01 00:00 [pubmed]
PHST- 1989/02/01 00:01 [medline]
PHST- 1989/02/01 00:00 [entrez]
AID - 10.1152/ajpregu.1989.256.2.R531 [doi]
PST - ppublish
SO  - Am J Physiol. 1989 Feb;256(2 Pt 2):R531-40. doi: 10.1152/ajpregu.1989.256.2.R531.