Insulin induced growth hormone response in fast-growing, lean and in slow-growing, obese pigs.

The effect of intravenous (IV) infusion of insulin on subsequent serum growth hormone (GH) response was studied in fasted lean, fast-growing and in genetically obese, slow-growing pigs at 6 months of age. A smaller GH response in obese compared to lean pigs was observed from 30 to 60 min after insulin infusion. Concurrently, marked hypoglycemia and a decrease in serum free fatty acids (FFA) were evident. Changes in serum glucose and FFA were similar in both pig strains. After IV administration of exogenous GH, the decrease in serum GH (half-life) and the simultaneous increase in serum FFA were not different for lean and obese pigs. The reduced GH secretory potential in obese pigs is consistent with reduced muscle development and growth rate.