Growth hormone and insulin combine to improve whole-body and skeletal muscle protein kinetics.
BACKGROUND
A cooperative effect of exogenous insulin and recombinant human growth hormone (r-hGH) with respect to whole-body and skeletal muscle protein metabolism has not been demonstrated previously. This study examined the effect of r-hGH and insulin administration during euglycemic clamping and concurrent amino acid supplementation.


METHODS
Twenty-three normal volunteers in the postabsorptive state were either treated with r-hGH for 3 consecutive days before a metabolic study (GH group; n = 10) or not treated (CTRL group; n = 13). The r-hGH dose was 0.2 mg/kg/day (n = 5) or 0.1 mg/kg/day (n = 5). All subjects then received an infusion of 14C-labeled leucine and tritiated phenylalanine, followed by measurement of baseline protein kinetics (GH and CTRL). Subsequently a euglycemic insulin infusion (1 mU/kg/min) with concurrent amino acid infusion was administered, and protein kinetic measurements were repeated at steady state.


RESULTS
GH and insulin separately produced an increase in whole-body and skeletal muscle protein net balance. GH plus insulin was associated with a higher net balance of protein than was insulin alone.


CONCLUSIONS
r-hGH and insulin in the presence of amino acids and glucose combine to improve whole-body and skeletal muscle protein kinetics.
Wolf
R F
RF
Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY 10021.
Heslin
M J
MJ
Newman
E
E
Pearlstone
D B
DB
Gonenne
A
A
Brennan
M F
MF
D000596:Amino Acids / Q000097:blood; D001786:Blood Glucose / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005542:Forearm / Q000098:blood supply; D005934:Glucagon / Q000097:blood; D013006:Growth Hormone / Q000494:pharmacology*; D006801:Humans; D007328:Insulin / Q000097:blood / Q000494:pharmacology*; D007700:Kinetics; D009124:Muscle Proteins / Q000378:metabolism*; D009994:Osmolar Concentration; D011506:Proteins / Q000378:metabolism*; D011994:Recombinant Proteins; D012039:Regional Blood Flow / Q000187:drug effects
D000596:Amino Acids; D001786:Blood Glucose; D007328:Insulin; D009124:Muscle Proteins; D011506:Proteins; D011994:Recombinant Proteins; D013006:Growth Hormone; D005934:Glucagon