Vitamin A influences the incretin hormone profiles by activating the retinoic acid receptor β.
Study Goal
The researchers aimed to investigate the impact of Vitamin A on intestinal glucose metabolic phenotypes, particularly its role in glucose-stimulated insulin secretion and GLP-1 expression.
Results Summary
Vitamin A deficiency (VAD) led to reduced glucose-stimulated insulin secretion and loss of intestinal GLP-1 expression, which were restored upon reintroducing Vitamin A. Activation of retinoic acid receptor β (RARβ) in STC-1 cells restored incretin hormone synthesis and secretory function.
Population
Male C57BL/6 mice
Effective Dosage
30 IU/g/d retinol for 10 days
Duration
12 weeks (VAD/VAN diet) + 10 days (retinol intervention) + 10 weeks (VAN diet)
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
VA-deficient diet (VAD) | decrease | glucose-stimulated insulin secretion | Male C57BL/6 mice | - | showed a decrease of | #1 |
VA-deficient diet (VAD) | decrease | intestinal glucagon-like peptide-1 (GLP-1) expression | Male C57BL/6 mice | - | a loss of | #2 |
reintroducing dietary VA to VAD mice | increase | intestinal VA levels | VAD mice | - | restored | #3 |
reintroducing dietary VA to VAD mice | increase | GLP-1 expression | VAD mice | - | restored | #4 |
reintroducing dietary VA to VAD mice | increase | normal glucose | VAD mice | - | restored | #5 |
incubation with retinol | increase | VA signaling factors expression | STC-1 cells | - | increased | #6 |
incubation with retinol | increase | retinoic acid receptor β (RARβ) expression | STC-1 cells | - | increased | #7 |
activation of RARβ | increase | intracellular incretin hormone synthesis | STC-1 cells | - | restored | #8 |
activation of RARβ | increase | secretory function | STC-1 cells | - | restored | #9 |
VA deficiency | decrease | intestinal glucose metabolic phenotypes | - | - | leads to an imbalance of | #10 |
BACKGROUND: This study aimed to investigate the impact of Vitamin A (VA) on intestinal glucose metabolic phenotypes. METHODS: Male C57BL/6 mice were randomized assigned to a VA-normal diet (VAN) or a VA-deficient diet (VAD) for 12 weeks. After12 weeks, the VAD mice were given 30 IU/g/d retinol for 10 days and VAN diet (VADN) for 10 weeks. By using glucose tolerance tests, immunofluorescence staining, quantitative polymerase chain reaction, siRNA transduction, and enzyme-linked immunosorbent assay, the glucose metabolic phenotypes as well as secretory function and intracellular hormone changes of STC-1 were assessed. RESULTS: VAD mice showed a decrease of glucose-stimulated insulin secretion and a loss of intestinal glucagon-like peptide-1 (GLP-1) expression. Through reintroducing dietary VA to VAD mice, the intestinal VA levels, GLP-1 expression and normal glucose can be restored. The incubation with retinol increased VA signaling factors expression within STC-1 cells, especially retinoic acid receptor β (RARβ). The activation of RARβ restored intracellular incretin hormone synthesis and secretory function. CONCLUSIONS: VA deficiency leads to an imbalance of intestinal glucose metabolic phenotypes through a mechanism involving RARβ signaling pathway, suggesting a new method to achieve the treatment for VAD induced glucose metabolism impairment.