[Plasma catecholamines, free and conjugated, in the hemodialyzed chronic renal failure patient]

Free, sulfo and glucuro-conjugated catecholamines (dopamine, noradrenaline and adrenaline) were measured to study their metabolism in 35 non-selected patients with chronic renal failure, and under hemodialysis for various periods of time. Our data demonstrate a statistically significant increase of free dopamine, and free noradrenaline concentration in these patients, while that of free adrenaline was not different from controls. However a careful scrutiny of 35 individual data suggests that sub-groups of patients with either high normal or low plasma free noradrenaline concentration could exist; this likely heterogeneity could be a good explanation for conflicting conclusions provided by previous reports. Suspecting that conjugated catecholamines might be altered in these patients, plasma sulfo and glucuro-conjugated amines were measured. We have found a predictable and highly significant increase of sulfo-conjugated catecholamines; glucuroconjugated dopamine and noradrenaline were unchanged, while glucuroconjugated adrenaline was significantly increased. The physiological meaning, if any, of these new observations on conjugated catecholamines cannot be assessed at the moment.