The location of the receptors involved in the human diuretic response to drinking an isotonic electrolyte solution.

Abstract

1. This study aimed to shed light on the receptors involved in the diuretic response to drinking isotonic fluids in man by employing a polyethylene glycol-based bowel lavage solution (Golytely) which is reported to cause no net movement of fluid across the gut. 2. Drinking Golytely resulted in a transient hypotonic diuresis. Mean urine flow rose from control values of 0.9 ml min-1 to 10.1 ml min-1 70 min after the start of drinking. The increase in urine output was accompanied by a fall in urine osmolality from control values of 879 mosM kg-1 to 105 mosM kg-1. The diuresis is similar to that produced by ingestion of an equal volume of an absorbable electrolyte-based solution (Tyrode). 3. Neither solution produced changes in plasma osmolality or electrolytes, but Golytely provoked a 6.8% contraction of plasma volume, whereas drinking Tyrode resulted in plasma expansion. Copious diarrhoea was experienced by all subjects who drank Golytely solution and by none on drinking Tyrode solution. 4. The infusion of Golytely into the stomach resulted in a hypotonic diuresis similar in magnitude to that elicited by drinking. Drinking with simultaneous aspiration of gastric contents ('sham-drinking') did not produce a significant diuresis. 5. Plasma arginine vasopressin (AVP) levels did not fall following the drinking of Golytely. The assay used was sufficiently sensitive to measure changes of 0.6 pg AVP (ml plasma)-1. 6. The findings show that signals from the oropharynx do not mediate the diuretic response to drinking Golytely in man and that a mechanism other than inhibition of AVP release appears to be involved. The receptors mediating this response may lie in the stomach and/or small bowel since Golytely is not absorbed, as evidenced by the contraction of plasma volume and diarrhoea.

Differences between sheep excreting sodium predominantly in their urine or in their faeces: the effect of changes in sodium intake

“…In this respect the recent demonstration that atrial natriuretic peptide, like anti-diuretic hormone (ADH) and aldosterone, exerts its effects on the intestine, as well as the kidney (Matsushita, Nishida, Hosomi & Tanaka, 1991), may be important. Similarly, Crotty, Gebruers & Hall (1992) have suggested that the diuretic response to isotonic electrolyte drinking may be partly mediated by enteric receptors and by hormones other than ADH. Vasoactive intestinal peptide could well be involved since it has natriuretic effects and both its plasma concentration and its metabolic clearance rate are affected by sodium intake (Davis, Shelley, MacDonald & Duggan, 1992).…”

Proceedings of the Physiological Society, 20‐21 September 1991, Dublin Meeting: Communications

“…These findings show no physiological basis on which to support this practice. Infusion of a bowel-lavage solution into the stomach of man leads to a hypotonic diuresis (Crotty et al 1988). Unlike physiological saline, bowellavage solutions, based on sodium sulphate and polyethylene glycol, are associated with minimal absorption or secretion (Davis et al 1980).…”