title: Insulin sensitivity of muscle protein metabolism is altered in patients with chronic kidney disease and metabolic acidosis.
abstract: An emergent hypothesis is that a resistance to the anabolic drive by insulin may contribute to loss of strength and muscle mass in patients with chronic kidney disease (CKD). We tested whether insulin resistance extends to protein metabolism using the forearm perfusion method with arterial insulin infusion in 7 patients with CKD and metabolic acidosis (bicarbonate 19 mmol/l) and 7 control individuals. Forearm glucose balance and protein turnover (2H-phenylalanine kinetics) were measured basally and in response to insulin infused at different rates for 2 h to increase local forearm plasma insulin concentration by approximately 20 and 50 μU/ml. In response to insulin, forearm glucose uptake was significantly increased to a lesser extent (-40%) in patients with CKD than controls. In addition, whereas in the controls net muscle protein balance and protein degradation were decreased by both insulin infusion rates, in patients with CKD net protein balance and protein degradation were sensitive to the high (0.035 mU/kg per min) but not the low (0.01 mU/kg per min) insulin infusion. Besides blunting muscle glucose uptake, CKD and acidosis interfere with the normal suppression of protein degradation in response to a moderate rise in plasma insulin. Thus, alteration of protein metabolism by insulin may lead to changes in body tissue composition which may become clinically evident in conditions characterized by low insulinemia.
authors: Department of Internal Medicine, Division of Nephrology, Dialysis and Transplantation, University of Genoa and IRCCS AOU San Martino-IST, Genoa, Italy.
authors: Giacomo
authors: G
authors: Garibotto
authors: Department of Internal Medicine, Division of Nephrology, Dialysis and Transplantation, University of Genoa and IRCCS AOU San Martino-IST, Genoa, Italy.
authors: Antonella
authors: A
authors: Sofia
authors: Department of Internal Medicine, Division of Nephrology, Dialysis and Transplantation, University of Genoa and IRCCS AOU San Martino-IST, Genoa, Italy.
authors: Rodolfo
authors: R
authors: Russo
authors: Department of Internal Medicine, Division of Nephrology, Dialysis and Transplantation, University of Genoa and IRCCS AOU San Martino-IST, Genoa, Italy.
authors: Ernesto
authors: E
authors: Paoletti
authors: Department of Internal Medicine, Division of Nephrology, Dialysis and Transplantation, University of Genoa and IRCCS AOU San Martino-IST, Genoa, Italy.
authors: Alice
authors: A
authors: Bonanni
authors: Department of Internal Medicine, Division of Nephrology, Dialysis and Transplantation, University of Genoa and IRCCS AOU San Martino-IST, Genoa, Italy.
authors: Emanuele L
authors: EL
authors: Parodi
authors: Department of Internal Medicine, Division of Nephrology, Dialysis and Transplantation, University of Genoa and IRCCS AOU San Martino-IST, Genoa, Italy.
authors: Francesca
authors: F
authors: Viazzi
authors: Department of Internal Medicine, Division of Nephrology, Dialysis and Transplantation, University of Genoa and IRCCS AOU San Martino-IST, Genoa, Italy.
authors: Daniela
authors: D
authors: Verzola