Possible Interaction: Insulin and Phenylalanine

“At day 28, insulin increased tCys (+8%), and the insulin-induced suppression of taurine and phenylalanine observed at day 0, but not that of BCAAs, was significantly impaired.”

“Nutritional intervention with taurine, phenyl alanine or branched chain amino acids can improve insulin sensitivity and post-prandial glucose disposal.”

“Bovine insulin enhanced the phenylalanine extraction when added to the medium at 250 ng/ml whereas no significant change was observed below this concentration.”

“In the intact rat hemidiaphragm in vitro 1 mU of insulin per ml caused a marked increase (40–70 per cent) of the incorporation of 14C-labelled phenylalanine into protein.”

“ Insulin … phenylalanine rate of appearance (μmol·kg-1·min-1), indicating suppression of muscle proteolysis, in both the control (1.02 ± 0.04 vs 0.76 ± … (0.89 ± 0.07 vs 0.61 ± 0.03) experiments, but the change was not different between the two experiments (P > 0.05).”

“Importantly, insulin increased net Leu and Phe balance across the leg and the balance between muscle protein synthesis and breakdown, but these changes were 45-140% lower (P < 0.03) in Pred than in placebo.”

“ Insulin in both trials similarly suppressed whole body flux of Leu and Phe.”

“CONCLUSION In summary, ph nylalanine in an amount moderately greater than that in a large protein meal stimulates an increase in ins ulin an d glucagon concentration.”

“In the hormone-infused arms, the addition of either insulin or IGF-I promoted greater positive shifts in phenylalanine balance than the aa alone arm (P < 0.01).”

“ Insulin also reduced (< 0.01) whole-body protein synthesis estimated from both the leucine model (nonoxidative leucine disposal) and the phenylalanine model (disposal of phenylalanine not accounted by its conversion to tyrosine).”

“The release of tyrosine and phenylalanine was significantly decreased from both leg and arm tissues (protein degradation) in response to insulin.”