Plasma amino acid concentrations during experimental hyperinsulinemia in 2 laminitis models.
J Vet Intern Med. 2021 Mar 11. doi: 10.1111/jvim.16095. Epub ahead of print. PMID: 33704816.
In humans, Hong et al. 2020 Parenteral amino acid supplementation with high dose insulin prevents hypoaminoacidemia during cardiac surgery stated that surgery triggers a stress response that produces insulin resistance and hyperglycemia; consequently during surgery high-dose insulin and dextrose are given to maintain normoglycemia, but this dramatically decreases plasma amino acids, and this hypoaminoacidemia limits protein synthesis after surgery. The research found that infusing amino acids during and immediately after surgery at a rate of amino acid kcal % equivalent to 35% of resting energy expenditure increased amino acid concentrations and prevented hypoaminoacidemia due to high-dose insulin therapy. However, infusing amino acids at the lower rate of 20% of resting energy expenditure did not prevent amino acid concentrations decreasing compared to pre-surgery fasting levels.
Trommelen et al. 2015 Mechanisms in endocrinology: Exogenous insulin does not increase muscle protein synthesis rate when administered systemically: a systematic review.
Amino acids and hyperaminoacidemia stimulate muscle protein synthesis.
IV insulin administration leads to a reduction in circulating plasma amino acid levels, with branched chain amino acids being most sensitive to an increase in circulating insulin levels - an insulin-induced hypoaminoacidemia.
Although some studies found insulin appeared to increase muscle protein synthesis, this only seemed to be at high levels of insulin.