Dexamethasone and GLP-2 given to lactating rat dams influence glucose uptake in suckling and postweanling offspring

Glucagon-like peptide-2 (GLP-2) enhances intestinal absorption in adult animals. Glucocorticosteroids accelerate the ontogeny of the intestine and increase sugar uptake in adult animals. Modifying the maternal diet during lactation alters nutrient uptake in the offspring. The authors hypothesized that GLP-2 and dexamethasone, when administrated to lactating rat dams, enhance sugar uptake in the suckling and postweanling offspring.

Rat dams were treated during lactation with GLP-2 (0.1 microg/g/day subcutaneously [SC], twice daily), dexamethasone (0.128 microg/g/day SC, once daily), GLP-2 + dexamethasone (same doses), or placebo. The suckling offspring were sacrificed at 19-21 days of age, and the postweanlings were sacrificed 4 weeks later. Intestinal glucose and fructose uptake was assessed using an in vitro ring technique.

GLP-2 and dexamethasone resulted in lower body weights, and dexamethasone caused intestinal atrophy in sucklings. The jejunal atrophy in sucklings given dexamethasone was prevented by GLP-2 + dexamethasone. In sucklings, the maximal transport rate and the Michaelis affinity constant for ileal glucose uptake were both increased by GLP-2 and GLP-2 + dexamethasone. In contrast, in postweanlings, the maximal transport rate for jejunal glucose uptake was reduced by dexamethasone and GLP-2, as was ileal fructose uptake.

Treating lactating rat dams with GLP-2 or dexamethasone enhances glucose uptake in sucklings, but the late effect is a reduction in glucose and fructose absorption in postweanlings. The nutritional significance of these findings remains to be established.