Ontogeny of renal renin release in spontaneously hypertensive rat and Wistar-Kyoto rat.
The role of renin-angiotensin system in generation of genetic hypertension is unclear. Renal renin secretion was examined in renal superficial cortical slices from spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) at 4 wk (prehypertensive), 6 wk (early hypertensive), and 12 wk (established hypertension) of age. Basal renin release in SHR was greater at 4 wk (749 +/- 55 vs. 480 +/- 50 ng/mg, P less than 0.005) and at 6 wk (428 +/- 70 vs. 266 +/- 60 ng/mg, P less than 0.02). Basal renin release declined by 43% between 4 and 6 wk and by 34% between 6- and 12-wk time periods in SHR. In SHR and WKY at all ages, renin responses to stimulation with isoproterenol (ISO, 10(-5) and 10(-6) M, respectively) were similar. Angiotensin II (ANG II) resulted in a significant reduction in renin release in both SHR and WKY at 10(-7) M in all age groups. The ANG II-induced percent change in renin release from control of SHR was less compared with WKY rats at 10(-8) and 10(-9)M at 4 wk of age. When ANG II was tested in presence of beta-adrenergic stimulation, a comparable renin inhibitory response was observed in both SHR and WKY. The number of ANG II-binding sites in proximal tubular brush-border membrane (BBM) was increased in SHR vs. WKY rats (458 +/- 18 vs. 235 +/- 12 fmol ANG II/mg BBM protein, P less than 0.001) at 4 wk of age. These data document increased basal renin release and ANG II-binding sites in proximal tubular BBM in 4 wk SHR compared with age-matched WKY rat.(ABSTRACT TRUNCATED AT 250 WORDS)
Henrich
W L
WL
Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas.
Levi
M
M
D000375:Aging / Q000502:physiology*; D000804:Angiotensin II / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D006973:Hypertension / Q000503:physiopathology*; D007545:Isoproterenol / Q000494:pharmacology; D007672:Kidney Cortex / Q000187:drug effects / Q000378:metabolism*; D007687:Kidney Tubules, Proximal / Q000378:metabolism; D008871:Microvilli / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D011943:Receptors, Adrenergic, beta / Q000502:physiology; D011945:Receptors, Angiotensin / Q000378:metabolism; D012083:Renin / Q000378:metabolism*; D012084:Renin-Angiotensin System / Q000502:physiology
D011943:Receptors, Adrenergic, beta; D011945:Receptors, Angiotensin; D000804:Angiotensin II; D012083:Renin; D007545:Isoproterenol