Insulin is an anabolic hormone with stimulatory effects on glucose and amino acid uptake, possibly protein synthesis, and bone growth, and inhibitory effects on protein breakdown. The precise role of insulin in the growth of healthy children is unclear, but two clinical models can be examined to illustrate insulin’s potential role in the growth of children. The cystic fibrosis (CF) patient, who exhibits poor linear growth and low lean body mass, may exhibit inadequate insulin secretion or impaired insulin action. The obese child typically has an excess of peripheral insulin, an associated acceleration of linear growth, and an accretion of lean body mass and adipose tissue. Speculation is offered on the putative role of exercise in affecting insulin action and secretion, which in turn could impact growth in children with CF or obesity.
Craig A. Horswill is with the Gatorade Exercise Physiology Laboratory, The Quaker Oats Co., 617 West Main Street, Barrington, IL 60010. William B. Zipf and C. Lawrence Kien are with The Ohio State University and Children’s Hospital, 700 Children’s Dr., Columbus, OH 43210. E. Bowie Kahle is with the Department of Biological Sciences at Marshall University, Huntington, WV 25701.