Influence of adiposity (genetic or hormonal) on the metabolism of amino acids and nutritional responses

Abstract

Summary ― The data published on the modifications of amino-acid metabolism associated with variations of obesity from genetic or hormonal origin have been reviewed. In the first part monogenic models of mice and rats are described. Obesity in humans is analysed in the second part. Lastly, non-ruminant genotypes or hormone-treated ones (chickens and pigs) are reviewed in the third part. Although different mechanisms are probably at the origin of these differences, many similarities can be drawn. Obesity is always associated with: 1) less efficient utilization of dietary amino acid; 2) a high concentration of branched-chain amino acids in plasma; 3) a deviation of carbon from amino acid towards gluconeogenis and lipogenesis; and 4) a less pronounced sensitivity to amino-acid imbalance in the diet.

GC-TOF/MS-based metabolomic profiling of estrogen deficiency-induced obesity in ovariectomized rats

“…They cannot be synthesized by the animal itself and must be supplied by the diet. In our study results, serum amino acid levels were elevated in obesity, which is consistent with previous research [49][50][51] . She et al [52] reported that obesity may play a potential role in the regulation of BCAA catabolism.…”

Obesity-related elevations in plasma leucine are associated with alterations in enzymes involved in branched-chain amino acid metabolism

“…obese humans (11,12,31). To begin to understand the molecular basis for the elevated plasma BCAA concentrations in obese animals, we examined the protein concentrations and activities of the enzymes catalyzing the first two key steps in body BCAA metabolism: BCATm and the BCKD enzyme complex in lean and obese ob/ob mice and Zucker rats.…”

“…obesity; mitochondrial branched chain amino acid transaminase; branched chain keto acid dehydrogenase; branched chain keto acid dehydrogenase kinase; ob/ob mice; Zucker rats; bariatric surgery; humans PLASMA CONCENTRATIONS of branched-chain amino acids (BCAAs) are elevated in humans and animal models of obesity (4,11,12,31,37,46,48,52,56). Although the plasma levels of other amino acids may also change in obesity, the rises in the BCAAs are of particular interest because they appear to have unique obesity-related effects.…”

“…Luzi et al (33) also concluded that the increased proteolysis in obesity was a result of impaired antiproteolytic action of insulin. An idea that has received less attention is that a reduction in BCAA metabolism might be involved (31). In lean animals, BCAA metabolism is highly regulated by changes in cellular BCAA concentrations due to alterations in dietary intake (20,51).…”

Genome-scale modelling of human adipocyte metabolism

“…Branched-chain amino acids (BCAAs: leucine, isoleucine and valine) are one such class of metabolites whose circulating levels are increased in individuals with obesity and insulin resistance [153][154][155][156][157][158][159][160][161]. BCAAs are three of the nine essential amino acids and account for 20% of total protein intake in the human diet [162][163][164][165].…”