Effects of Human Growth Hormone on the Porto-Arterial Concentration Differences of Glucose and Amino Acids in the Newborn Piglet

It is known that growth hormone (GH) increases the mitotic index of duodenal crypt cells. In early life, such an effect could be of particular importance for the functional development of the intestine in terms of absorptive capacity. In this study, osmotic mini pumps were introduced into the abdominal cavity of newborn piglets. The pumps permitted a continuous infusion of either recombinant human growth hormone (rhGH) at a rate of 0.1 IU GH × kg^-1 × 24 h^-1 or of vehicle. After 7 days of treatment, a bolus of amino acids and glucose was infused into the duodenum. Following this bolus, there was a prompt rise in the plasma concentration of both amino acids and glucose, especially in blood withdrawn from the portal vein. Thus, when the differences in concentrations of both amino acids and glucose between portal and arterial blood plasma were calculated, these differences reached maximum values between 30 and 60 minutes after the bolus. In animals treated with GH, maximum values occurred at a lower level than in control animals. These reductions were in the order of 60% (P > 0.01) if calculated over the first hour of absorption. From this study, it might be concluded that GH does not improve the absorptive capacity of the small intestine in newborn piglets. Instead, GH seems to reduce the absorption dynamics of glucose and amino acids. The reason for this is obscure, but could imply a specific effect of GH on enterocyte function.

Key words

Growth Hormone - Small Intestine - Piglet - Amino Acids - Glucose - Porto-Arterial Concentration Differences - Catheterization