Figure 1.

Effects of dietary sugars on intestinal Ca²⁺ transport in lactating and virgin rats. A) Active transepithelial Ca²⁺ transport from the luminal to the basolateral compartment was initially expressed as a ratio of [⁴⁵Ca²⁺ inside (basolateral)/⁴⁵Ca²⁺ outside (luminal)] of everted gut sacs obtained from the duodenum of lactating dams and virgin rats fed a glucose (G), fructose (F) or starch (S) diet for 6 wk. B) Ca²⁺ uptake by the intestinal cells was calculated as the accumulation of ⁴⁵Ca²⁺ dpm · mg⁻¹ · min⁻¹ of duodenum. Data in panels A and B were normalized to levels in virgins fed S. Bars represent relative transport rate (n=5–8/group). C) Active transepithelial Ca²⁺ transport was measured using everted intestinal sacs from the duodenum or proximal jejunum of dams fed a G, F, or S diet for 6 wk. Data were normalized relative to transepithelial Ca²⁺ transport in the duodenum of pregnant dams fed S (n=4/group). D) Paracellular Ca²⁺ transport was measured in the same rats in panel C, using noneverted intestinal sac from the proximal jejunum. Data were normalized to paracellular Ca²⁺ transport in the jejunum of pregnant dams fed S. Values represent means ± se. Differences (P<0.05) among means, indicated by differences in superscript letters, were analyzed by 1-way ANOVA LSD after a 2-way ANOVA showed significant diet or lactation effects. ^♦P < 0.05 vs. virgins.