The first steps of leucine utilization are reversible deamination to α-ketoisocaproic acid (α-KIC) and irreversible oxidation. Recently the regulatory role of leucine deamination over oxidation was underlined in rodents. Our aim was to measure leucine deamination and reamination in the whole-body, in respect to previously determined rates across organs, in humans. By leucine and KIC isotope kinetics, we determined whole-body leucine deamination and reamination, and we compared these rates to those already reported across the sampled organs. As an in vivo counterpart of the "metabolon" concept, we analysed ratios between oxidation to either deamination or reamination. Leucine deamination to KIC was greater than KIC reamination to leucine in the whole-body (p=0.005), muscle (p=0.005) and the splanchnic area (p=0.025).These rates were not significantly different in the kidneys. Muscle accounted for ≈60% and ≈78%, the splanchnic bed for ≈15% and ≈15%, and the kidney for ≈12% and ≈18%, of whole-body leucine deamination and reamination rates, respectively. In the kidney, percent leucine oxidation over either deamination or reamination was >3-fold greater than muscle and the splanchnic bed. Skeletal muscle contributes by the largest fraction of leucine deamination, reamination and oxidation. However, in relative terms, the kidney plays a key role in leucine oxidation.

The contribution of muscle, kidney and splanchnic tissues to leucine transamination in humans

Garibotto, Giacomo;Verzola, Daniela;
2017

Abstract

The first steps of leucine utilization are reversible deamination to α-ketoisocaproic acid (α-KIC) and irreversible oxidation. Recently the regulatory role of leucine deamination over oxidation was underlined in rodents. Our aim was to measure leucine deamination and reamination in the whole-body, in respect to previously determined rates across organs, in humans. By leucine and KIC isotope kinetics, we determined whole-body leucine deamination and reamination, and we compared these rates to those already reported across the sampled organs. As an in vivo counterpart of the "metabolon" concept, we analysed ratios between oxidation to either deamination or reamination. Leucine deamination to KIC was greater than KIC reamination to leucine in the whole-body (p=0.005), muscle (p=0.005) and the splanchnic area (p=0.025).These rates were not significantly different in the kidneys. Muscle accounted for ≈60% and ≈78%, the splanchnic bed for ≈15% and ≈15%, and the kidney for ≈12% and ≈18%, of whole-body leucine deamination and reamination rates, respectively. In the kidney, percent leucine oxidation over either deamination or reamination was >3-fold greater than muscle and the splanchnic bed. Skeletal muscle contributes by the largest fraction of leucine deamination, reamination and oxidation. However, in relative terms, the kidney plays a key role in leucine oxidation.
File in questo prodotto:
File Dimensione Formato  
cjpp-2017-0439pr.pdf

accesso aperto

Tipologia: Documento in Post-print
Dimensione 613.2 kB
Formato Adobe PDF
613.2 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11567/885480
Citazioni
  • ???jsp.display-item.citation.pmc??? 3
  • Scopus 5
  • ???jsp.display-item.citation.isi??? 5
social impact