Jaakko Linkola

Renin, Water drinking, salt preference and blood pressure in alcohol preferring and alcohol avoiding rats

Mechanisms controlling fluid volume were studied in alcohol preferring AA (Alko, Alcohol) and alcohol avoiding ANA (Alko, Non-Alcohol) rats. Hypertonic sodium chloride solution (5%) given orally caused a higher dipsogenic response in AA rats than in the ANAs. One hour after ethanol loading (4.8 g/kg, by stomach tube), plasma renin activity of AA rats was four times as high as in ANA rats. ANA rats had higher degree of sodium chloride (0.9%) preference and higher blood pressure. The strain differences in voluntary salt intake and salt metabolism may modulate the consumption of calories and water as well as blood pressure and different reactivity of the renin system in AA and ANA rats.

Renin-aldosterone axis in ethanol intoxication

The effect of acute moderate ethanol intoxication on renin-aldosterone axis was studied in four healthy humans in normal sodium and water balance. The subjects drank ethanol 1.2 g/kg body weight during 90 minutes. A dissociation between plasma renin activity (PRA) and plasma aldosterone took place; PRA increased (p less than 0.001) and aldosterone showed a decreasing trend, which was not significant. Serum Na+/K+-ratio increased (p less than 0.001). We observed no significant change in serum osmolality, blood pressure nor heart rate. The increase (p less than 0.001). We observed no significant change in serum osmolality, blood pressure nor heart rate. The increase in PRA was probably caused primarily by dehydration due to ethanol diuresis. The dissociation between plasma aldosterone and PRA may be associated with increasing serum Na+/K+-ratio or an inhibitory action of ethanol on aldosterone secretion.