Is dopamine a physiological natriuretic hormone in the dog?
Both plasma and urinary dopamine and noradrenaline were measured as free and sulphate conjugates, by a radioenzymatic method, before and during extracellular volume expansion (ECVE) with hypo-, iso- or hyper-tonic fluid (usually sodium chloride solution) in dogs. During ECVE there was a decrease in plasma catecholamine concentration. For all cases except noradrenaline, this is probably due to a dilution phenomenon since when results were expressed as pg/mg of protein, ECVE had no effect. This change in noradrenaline accounted for the increase in the dopamine/noradrenaline ratio. As expected, there was an increase in the urinary excretion of dopamine during ECVE with both iso- and hyper-tonic fluid. This increase was not observed in the group of dogs given hypotonic fluid, although the increase of fractional excretion of sodium was of a similar order of magnitude. The increase in the urinary excretion of dopamine was apparently not affected by an increase in plasma sodium concentration and/or osmolality. The demonstrated dissociation between sodium and dopamine in urine does not support a physiological role for dopamine in renal handling of sodium during ECVE, and raises the question of its specificity.
D000818:Animals; D001834:Body Water / Q000378:metabolism; D004285:Dogs; D004298:Dopamine / Q000378:metabolism / Q000502:physiology*; D005110:Extracellular Space / Q000378:metabolism; D005260:Female; D008297:Male; D009318:Natriuresis; D009638:Norepinephrine / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000008:administration & dosage
D012965:Sodium Chloride; D012964:Sodium; D004298:Dopamine; D009638:Norepinephrine