Intestinal adaptation is a complex physiologic process that is not completely understood. Intravenous
short-chain fatty acids (SCFAs) enhance intestinal adaptation after 80% enterectomy in rats. The purpose of this study was to examine rapid responses to SCFA-supplemented
total parenteral nutrition (TPN) in the normal small intestine. After jugular catheterization, 31 Sprague-Dawley rats (weighing 258 +/- 3 g) were randomly assigned to receive standard TPN or an isoenergetic, isonitrogenous TPN
solution supplemented with SCFAs (TPN+SCFA). Intestinal samples were obtained after 24 or 72 h of nutrient infusion. TPN+SCFA for 24 h increased (P < 0.05) the ileal
RNA concentration (microg
RNA/mg ileum) whereas TPN+SCFA for 72 h increased (P < 0.05) the ileal
DNA concentration (microg
DNA/mg ileum) and decreased (P < 0.05) the ileal
protein concentration (microg
protein/mg ileum). Ileal
proglucagon mRNA abundance was elevated (P < 0.05) after 24 h of TPN+SCFA infusion and returned to levels seen with control TPN by 72 h.
Glucose transporter 2 (GLUT2)
mRNA was significantly higher (P < 0.05) in the TPN+SCFA groups at both time points when compared with control TPN groups. Ileal
GLUT2 protein abundance in the 72-h TPN+SCFA group was significantly higher (P < 0.05) than that of all other groups.
Sodium-glucose cotransporter (SGLT-1)
mRNA and
protein abundance and uptake of D-
fructose and
D-glucose did not differ between groups. Jejunal uptake of
L-glucose and
lauric acid was significantly higher (P < 0.05) after 72 h of TPN+SCFA than after 24 h, whereas the 24- and 72-h TPN groups did not differ. In summary, SCFAs led to rapid changes in ileal
proglucagon and
glucose transporter expression in rats receiving TPN and provide insights into therapeutic management of individuals with
short bowel syndrome or intestinal
malabsorption syndromes.