Effects of ethanol ingestion and urinary acidity on the metabolism of triethylamine in man

In four volunteers exposed to triethylamine (TEA) by inhalation (20 mg/m3, 8 h), the nonrenal clearance of TEA into triethylamine-N-oxide (TEAO) was inhibited by 15 to 30% by intake of ethanol (blood serum level in average 25 mmol/l). Ethanol intake caused a decrease of plasma levels of TEA and TEAO, and of the fractional formation of TEAO. This may partly be due to a second effect of ethanol; it caused a slight decrease of urinary pH, which led to an increase of the urinary TEA excretion rate, with a possible withdrawal of TEA from oxygenation. Indeed, this effect was efficiently counteracted by intake of sodium bicarbonate, which caused a decrease of renal clearance of TEA, and increases of plasma levels of TEA and TEAO, and of the fractional formation of TEAO. A change of urinary pH by about two units caused a change of renal clearance of TEA by a factor of three and of the oxygenation by two. The renal clearance of TEAO was not affected by urinary pH.