Folic acid supplementation modifies β-adrenoceptor-mediated in vitro lipolysis of obese/diabetic (+db/+db) mice

The effects of folic acid (5.7 and 71 µg/kg, 4 weeks) consumption on the β-adrenoceptors (β-ARs)-elicited lipolysis in vitro of the abdominal adipocytes of lean/control (+m/+db) and obese/diabetic (+db/+db) mice (female) were investigated. β-AR agonists (salbutamol, a β₂-AR agonist; BRL 37344 and CGP 12177, β₃-AR agonists; adrenaline, a β-AR agonist)-mediated lipolysis, β₂-, and β₃-ARs protein expression of the adipose tissues after folic acid consumption were evaluated. Our results demonstrate that a smaller magnitude of the basal (spontaneous) and the β-AR agonists-triggered lipolysis was observed in +db/+db mice, and folic acid supplementation (71 μg/kg) resulted in an improvement of both the baseline and the β-ARs-mediated lipolysis. In controls, a lower β₂- and β₃-ARs protein expression of the adipose tissues was detected in +db/+db mice, compared to +m/+db mice. In both strains fed with folic acid (71 μg/kg), a reduction of β-AR protein expression was observed compared to the respective controls. In +db/+db mice, folic acid (5.7 and 71 μg/kg) consumption caused a dose-dependent increase of β₃-AR protein expression compared to controls. We demonstrate that lipolysis elicited by β-AR (β₂- and β₃-ARs) agonists was blunted in +db/+db mice. Folic acid consumption has significant modulatory effects on β-ARs protein expression and lipolysis.