Sex influence on renal alpha 2-adrenergic receptor density in the spontaneously hypertensive rat.
Male spontaneously hypertensive rats (SHR) have higher blood pressure than females. We compared renal alpha 2-adrenergic receptor density among intact SHR and Wistar-Kyoto (WKY) rats of both sexes, male and female SHR gonadectomized at 4 weeks of age, and gonadectomized SHR supplemented with testosterone. Additional groups of SHR were treated with enalapril (30 mg/kg per day), an angiotensin-converting enzyme inhibitor, from 5 to 14 weeks of age. Renal alpha 2-adrenergic receptor density was higher in males than females in both SHR and WKY rats. Female SHR and WKY rats had identical low renal alpha 2-adrenergic receptor density. Castration of male SHR reduced the male-female differences in blood pressure and renal alpha 2-adrenergic receptor density by 60%. Treatment with testosterone raised blood pressure and renal alpha 2-adrenergic receptor density to the intact male levels in both gonadectomized males and females. Treatment with enalapril decreased blood pressure but not renal alpha 2-adrenergic receptor density in both male and female SHR. We conclude that (1) both renal alpha 2-adrenergic receptor density and blood pressure are influenced by sex in SHR and WKY, (2) renal alpha 2-adrenergic receptor density like blood pressure is regulated by androgens, and (3) increased renal alpha 2-adrenergic receptor density is not a consequence of high blood pressure in male SHR.
Gong
G
G
Department of Medicine, Creighton University School of Medicine, Omaha, Neb. 68131.
Dobin
A
A
McArdle
S
S
Sun
L
L
Johnson
M L
ML
Pettinger
W A
WA
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004656:Enalapril / Q000494:pharmacology; D005260:Female; D006973:Hypertension / Q000378:metabolism*; D007668:Kidney / Q000737:chemistry*; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D018341:Receptors, Adrenergic, alpha-2 / Q000032:analysis*; D012737:Sex Factors
D018341:Receptors, Adrenergic, alpha-2; D004656:Enalapril