Circadian variations of plasma renin activity and plasma osmolality in various physiological and pathological states

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.

Studies on renin release from isolated superfused glomeruli: effects of temperature, urea, ouabain and ethacrynic acid

1. The effects of different energy substrates, of low temperature, of urea, and of ouabain and ethacrynic acid were studied on the rate of renin release from viable juxtaglomerular cells during superfusion of isolated rat glomeruli. 2. Neither lactate nor glutamate altered renin release rate from that observed using glucose as the sole energy substrate. Succinate 10 mM elevated release transiently but did not influence the release caused by reductions in osmolality through lowering sucrose concentration. 3. Peak renin release was more prolonged and returned more slowly to control following reductions in osmolality in phosphate-Ringer than in bicarbonate-Ringer. 4. At 37 degrees C, the peak of renin released induced by hypo-osmolality was smaller and delayed, and returned earlier to control than at 30 degrees C. Reduction in temperature from 30 to 4 degrees C resulted in a 32-fold increase in basal release rate. At 4 degrees C a 20 m-osmole/kg reduction in tonicity caused an additional 2-5-fold increase in release rate. 6. Increasing superfusate osmolality with urea did not affect basal renin release but 100 mM urea suppressed the releasing effect of a 15 mM reduction in NaCl concentration. 7. Ouabain (10(-4) M) caused a small (33 +/- 9%, P less than 0-025) transient increase in renin release. Ethacrynic acid (10(-3) M) provoked a progressive increase in release reaching 100 +/- 15% above control within 50 min. In the presence of both inhibitors the release provoked by hyposmolality was prolonged. 8. It is concluded that renin release in vitro is a function of actively regulated cell volume and it is proposed that a similar mechanism could underline both barorecptor and macula densa controls of renin secretion in vivo.

Renin-aldosterone axis in ethanol intoxication and hangover

The renin-aldosterone system was studied in human volunteers during ethanol intoxication and hangover. Plasma renin activity increased more than 100%, when 1.5 - 2.3 g ethanol per kg body weight was ingested over a three hour period. During hangover the increase even exceeded 200%. Plasma aldosterone concentration decreased during ethanol intoxication, but increased greatly during hangover. It is suggested that the stimulation of the renin-aldosterone axis during ethanol intoxication and hangover is due to dehydration and increased activity of the sympathetic nervous system.