Ethanol- and threonine-induced hypertension in rats: a common mechanism

To investigate the effects of oral L-threonine and ethanol, precursor of endogenous acetaldehyde, on systolic blood pressure, cystolic free calcium ([Ca2+]i) and vascular calcium uptake in Wistar-Kyoto (WKY) rats.

Twenty-four male WKY rats aged eight weeks were divided into four groups of six animals each. Animals were given either water or 5% ethanol, 8% L-threonine or 8% L-glycine in drinking water for 15 weeks, animals were sacrificed, aortic rings were incubated in physiological buffer containing 45Ca2+ and uptake was measured after 20 mins. ([Ca2+]i in platelets was measured with a fluorescence [Ca2+]i indicator, FURA-2. Tissues were processed for morphological investigation.

After 15 weeks, systolic blood pressure, platelet [Ca2+]i and aortic calcium uptake were all significantly higher (P < 0.001) in rats given either threonine or ethanol than in control rats given water or glycine. Animals in threonine or ethanol group also showed smooth muscle cell hyperplasia, with some thickening of the wall and narrowing of the lumen in small arteries and arterioles of the kidney. Glycine treatment did not cause any of these changes in rats.

These results suggest that acetaldehyde may be a common cause of both ethanol- and threonine-induced hypertension.