Adrenocorticosteroid excretion in salt-sensitive and salt-resistant spontaneously hypertensive rats.
Two strains of spontaneously hypertensive rats (SHRs) differ in their susceptibility to the hypertensive effects of dietary NaCl. One strain exhibits a significant elevation of blood pressure after dietary NaCl loading (SHR-S), whereas the other does not (SHR-R). Since differences in adrenocortical steroid production may contribute to NaCl sensitivity, we compared 19-nordeoxycorticosterone (DOC), 18-OH-DOC, aldosterone, and corticosterone excretion in 6-week-old male rats from the SHR-S (n = 24) and SHR-R (n = 24) strains. The rats were housed in metabolic cages (two rats per cage) and given either basal (1%) or high (8%) NaCl diet. Urinary steroids were analyzed using thin-layer chromatography and radioimmunoassay methods. The high NaCl diet elevated the urinary excretion of the four corticosteroids in both rat strains. 19-nor-DOC decreased with time in both the SHR-S and SHR-R strains, and was not different between strains on either diet. Aldosterone was increased in the SHR-S strain compared with the SHR-R strain on the low NaCl diet, but aldosterone was not different between the two strains on the high NaCl diet. Corticosterone and 18-OH-DOC did not differ between strains. These data confirm that 19-nor-DOC is higher in young prehypertensive SHRs and decreases with age. Aldosterone excretion is higher in the SHR-S strain compared with the SHR-R strain on the low NaCl diet.(ABSTRACT TRUNCATED AT 250 WORDS)
Griffing
G T
GT
Evans Memorial Department of Clinical Research, University Hospital, Boston University Medical Center, Massachusetts 02118.
Melby
J C
JC
Holbrook
M
M
Wilson
T C
TC
Wyss
M J
MJ
D000450:Aldosterone / Q000652:urine; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002855:Chromatography, Thin Layer; D003345:Corticosterone / Q000652:urine; D003900:Desoxycorticosterone / Q000031:analogs & derivatives / Q000652:urine; D006889:Hydroxycorticosteroids / Q000652:urine*; D006973:Hypertension / Q000652:urine*; D008297:Male; D011863:Radioimmunoassay; D051381:Rats; D011918:Rats, Inbred SHR; D012982:Sodium, Dietary / Q000008:administration & dosage / Q000494:pharmacology*
D006889:Hydroxycorticosteroids; D012982:Sodium, Dietary; C042509:18-hydroxydeoxycorticosterone; D003900:Desoxycorticosterone; C019026:19-nordeoxycorticosterone; D000450:Aldosterone; D003345:Corticosterone