Relationship between Renal Prostaglandin E and Renal Sodium Handling during Water Immersion in Normal Man

    loading  Checking for direct PDF access through Ovid

Abstract

SUMMARY

Previous studies from this laboratory have demonstrated that the central hypervolemia induced by water immersion to the neck (NI) constitutes a suitable model for assessing the hormonal response to volume expansion without concomitant alterations in plasma composition. The NI model was used to assess in a kinetic fashion the relationship between renal prostaglandin E (PGE) and renal sodium handling. Nine normal subjects were studied twice in the sodium-replete state during NI: with indomethacin (Ind) pretreatment (50 mg q6h x 6)(NI + Ind) and without indomethacin (NI). Urinary sodium, potassium, and PGE excretion (UPGEV) were measured hourly. NI was associated with marked increases in UN.V [from 87 ± 20 (SE) to 219 ± 25 μEq/min (P < 0.06)] and UpGKV[from 6.4 ± 1.4 to 12.9 ± 2.5 ng/min (P < 0.05)]. Although indomethacin administration lowered the basal rate of UPGBV prior to immersion, it neither prevented the subsequent augmentation of UPGEV during NI + Ind nor affected the magnitude of the natriuresis during NI + Ind. Subsequently, six of the subjects were restudied following dietary sodium restriction (10 mEq/day). The changes in UPGBV during NI and NI + Ind were qualitatively similar to those observed in the sodium-replete state. In contrast to the sodium-replete studies, however, the natriuresis of immersion was attenuated markedly by indomethacin pretreatment. In summary, the data demonstrate that immersion-induced central volume expansion is associated with a striking increase in renal PGE excretion which is attenuated but not prevented by indomethacin. In addition, indomethacin administration attenuates markedly the natriuretic response of immersion in sodium-depleted, but not in sodium-replete, normal subjects. These observations are consistent with the suggestion that renal PGE may constitute a determinant of the renal response to volume expansion in sodium-depleted man. Circ Res 45: 71-80, 1979

Related Topics

    loading  Loading Related Articles