Can gastrointestinal hormones enhance intestinal absorption?

Area of Science:

• Gastroenterology
• Endocrinology
• Developmental Biology

Background:

• Gastrointestinal peptides are known to influence small intestinal function.
• The trophic effects of glucagon and cholecystokinin-octapeptide (CCK-OP) on intestinal absorption require further investigation.

Purpose of the Study:

• To evaluate the impact of chronic glucagon and CCK-OP administration on substrate absorption in both developing and mature rat small intestines.
• To determine the differential effects of these hormones on galactose and glycine absorption in various segments of the small intestine.

Main Methods:

• Utilized a rat fetal intestine transplant model for developing intestine and in situ isolated jejunal and ileal segments for mature intestine.
• Administered glucagon (10 µg/kg/day) and CCK-OP (45 µg/kg/day) continuously for 14 days via osmotic pumps.
• Assessed intestinal absorption of 14C-galactose and 14C-glycine using a recirculation perfusion technique.

Main Results:

• In fetal intestine, glucagon increased galactose and glycine absorption by 13% and 27%, respectively; CCK-OP increased them by 11% and 17%.
• In mature jejunum, glucagon significantly enhanced galactose (53%) and glycine (55%) absorption. CCK-OP decreased galactose absorption by 3% but increased glycine absorption by 41%.
• In mature ileum, glucagon increased galactose absorption by 271% (p<0.05) and glycine by 21%. CCK-OP increased galactose absorption by 224% (p<0.05) and glycine by 19%.

Conclusions:

• Chronic administration of glucagon and CCK-OP demonstrates the capacity to augment substrate absorption in both developing and mature rat small intestines.
• These findings indicate that modulating the gastrointestinal hormone milieu could be a viable strategy for enhancing intestinal absorption, potentially applicable to human conditions.