AJP - Heart and Circulatory Physiology, Vol 248, Issue 4 445-H451, Copyright © 1985 by American Physiological Society
An antihypertensive substance associated with erythrocytes
W. D. McCumbee, G. O. Rankin and G. L. Wright
An extract was prepared from hemolyzed erythrocytes of spontaneously
hypertensive rats (SHR) which inhibits lanthanum-resistant calcium uptake
by aortic segments and lowers blood pressure in several models of
hypertension. Erythrocyte hemolysates were extracted with Triton X-100 and
partially purified by boiling and Sephadex G-150 column chromatography. The
effects of the extract on calcium uptake by aortic segments in vitro were
reversible and dose dependent. The extract was administered by
intraperitoneal injection to male and female SHR, deoxycorticosterone-NaCl
hypertensive rats (DOCA-NaCl), one-kidney one-clip (1K,1C) and two-kidney,
one-clip (2K,1C) renovascular hypertensive rats, and their appropriate
control groups. At 24 h postinjection, the antihypertensive factor (AHF)
lowered the systolic blood pressure (SBP) in the conscious SHR male (200
+/- 7 to 132 +/- 11 Torr), SHR female (172 +/- 4 to 117 +/- 11), DOCA-NaCl
(187 +/- 6 to 121 +/- 8), 2K,1C (165 +/- 8 to 127 +/- 7), and 1K,1C (167
+/- 8 to 146 +/- 13) models of hypertension. The duration of the effect on
the SBP was model dependent. The SBP was significantly decreased for 4-8
days in SHR, 4 days in 1K,1C and 2K,1C, and 2 days in DOCA-NaCl. In
contrast to the results obtained in hypertensive rats, AHF had little
effect on the SBP of normotensive animals. Both the blood pressure and
calcium effects were abolished by digestion with phospholipase D,
tentatively suggesting that the compound(s) inducing these effects may be a
phospholipid or have a phospholipid moiety.
