1H NMR study of renal trimethylamine responses to dehydration and acute volume loading in man

Proc Natl Acad Sci U S A. 1991 Jul 15;88(14):6053-7. doi: 10.1073/pnas.88.14.6053.

Abstract

We have used volume-localized 1H NMR spectroscopy to detect and measure changes in medullary trimethylamines (TMAs) in the human kidney in vivo. Localized water-suppressed 1H spectra were collected from a volume of interest located within the renal medulla by using a stimulated echo-based localization scheme. The principal resonances in the medullary 1H spectrum were residual water (4.7 ppm), lipid (0.9-1.4 ppm), and TMAs (3.25 ppm). The TMA line width was 7-15 Hz before filtering, and the signal-to-noise ratio was 40:1. In four normal volunteers, 15 hr of dehydration led to a significant increase in urine osmolality and decrease in body weight and an increase in medullary TMAs. A subsequent water load [20 ml.(kg of body weight)-1] caused a transient water diuresis, a return to euvolemic body weight, and a significant reduction in medullary TMAs within 4 hr. These results suggest that TMAs may play an osmoregulatory role in the medulla of the normal human kidney.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Dehydration / physiopathology*
  • Drinking
  • Humans
  • Hydrogen
  • Kidney / physiology*
  • Kidney Medulla / physiology
  • Magnetic Resonance Spectroscopy / methods
  • Male
  • Methylamines*
  • Water

Substances

  • Methylamines
  • Water
  • Hydrogen
  • trimethylamine