3-Aminoisobutyric acid is a non-protein amino acid formed during thymine catabolism.1 It induces browning in primary adipocytes, increasing the expression of uncoupling protein 1 (UCP-1) and CIDEA when used at a concentration of 5 µM. It also increases the expression of PPARα in primary adipocytes and in mouse inguinal white adipose tissue (WAT) in vivo and increases β-oxidation in hepatocytes. Plasma levels of 3-aminoisobutyric acid are increased in mice following exercise and, when administered at a dose of 100 mg/kg per day, it decreases weight gain and body fat percentage without decreasing food intake or increasing energy expenditure, and improves glucose tolerance. Levels of 3-aminoisobutyric acid are elevated in the plasma, urine, and cerebrospinal fluid of patients with β-ureidopropionase deficiency, a disorder characterized by an inborn error of pyrimidine degradation.2
1.Roberts, L.D., BostrÖm, P., O'Sullivan, J.F., et al.β-Aminoisobutyric acid induces browning of white fat and hepatic β-oxidation and is inversely correlated with cardiometabolic risk factorsCell Metab.19(1)96-108(2014) 2.van Kuilenburg, A.B., Meinsma, R., Beke, E., et al.β-Ureidopropionase deficiency: An inborn error of pyrimidine degradation associated with neurological abnormalitiesHum. Mol. Genet.13(22)2793-2801(2004)