Plasma and urinary catecholamines as related to renal function in man

Area of Science:

• Nephrology
• Endocrinology
• Cardiovascular Physiology

Background:

• Progressive kidney disease and essential hypertension are associated with reduced renal plasma flow (ERPF) and glomerular filtration rate (GFR).
• The relationship between declining kidney function and catecholamine levels (norepinephrine and epinephrine) requires further investigation.

Purpose of the Study:

• To evaluate the association between ERPF and GFR and plasma or urinary norepinephrine (NE) and epinephrine (E) levels in patients with varying degrees of non-oliguric renal impairment.
• To determine if catecholamine levels are affected by chronic kidney disease or essential hypertension.

Main Methods:

• Simultaneous assessment of ERPF, GFR, plasma NE and E, and urinary NE and E excretion.
• Study population included normal subjects, patients with parenchymal kidney disease, and patients with essential hypertension.

Main Results:

• ERPF and GFR were significantly lower in patients with renal disease and essential hypertension compared to normal subjects.
• Plasma and urinary NE and E levels did not differ significantly among groups, showing no clear relationship with ERPF or GFR.
• A significant reduction in urinary NE and E excretion was observed only when GFR fell below 20 ml/min.

Conclusions:

• Chronic reduction in kidney excretory function does not substantially impact circulating norepinephrine and epinephrine levels.
• Urinary excretion of NE and E distinctly decreases in advanced renal failure (GFR < 20 ml/min).
• These findings are important for interpreting catecholamine studies in patients with impaired kidney function, considering potential alterations in urinary excretion at later stages.