Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, PCA245

Poster Communications

High-Dose Perinatal Folic-Acid Supplementation Alters Insulin Sensitivity in Sprague-Dawley Rats and Decreases Adiponectin Expression

A. O. Morakinyo1, T. A. Samuel2, F. O. Awobajo1, G. O. Oludare1, A. Mofolorunso1

1. Physiology, University of Lagos, Lagos, Nigeria. 2. Biochemistry, University of Lagos, Lagos, Nigeria.

  • Schematic illustration of the study design. FAS = folic acid supplementation.

Altered nutritional environment during foetal and neonatal development leads to detrimental effects in offspring health later in life. Micronutrient supplementation in pregnant women may be a promising strategy for reducing these adverse outcomes. For instance, folic acid supplementation has been recommended prior to and during pregnancy, to reduce the risk of infant neural tube defects. However, the unintended consequences of folic acid supplementation (FAS) during pregnancy, potentially in excess of the recommended upper levels, is a matter of critical importance. This study examined the offspring of female rats exposed to high FAS during pregnancy and/or lactation to determine the effects on glucose tolerance, insulin sensitivity, lipid metabolism, and expression of adiponectin in the offspring. Twenty (20) female Sprague-Dawley rats were divided into four groups (n=5). Control (CTR) rats received normal rat chow, while the treatment groups received FAS either during gestation (FC), lactation (CF) or both periods (FF). Food and water intake measured daily. Lipid concentrations were determined with an automatic blood chemical analyzer; insulin and adiponectin levels were measured using ELISA. Glucose tolerance and insulin sensitivity were also determined to evaluate glucose homeostasis. The obtained data was analyzed by GraphPad Prism (v. 5) using One-way analysis of variance (ANOVA). Data expressed as mean ± standard error of mean (SEM) and the significant level was set at p<0.05. The quantity of postweaning feed and water consumed by FAS rats was significantly (p< 0.05) higher than that of the control. In addition, triglyceride (e.g. 1.30±0.06 vs. 0.73±0.04, FC vs. CTR; p< 0.05) and insulin (e.g. 93.36±10.27, 91.0±8.94; CF & FF respectively) levels were elevated (p< 0.05) compared with control (79.78±8.41) but insulin insensitivity was exacerbated (e.g. AUC 627±25.08 vs. 789±26.57, CF vs. CTR; p< 0.05) in adult offspring. The expression of adiponectin in insulin-sensitive gastrocnemius muscles was also significantly decreased (e.g. 754.93±99.62, 492.64±82.03 vs. 1118.6±108.29; CF, FC vs. CTR) and these were consistent with insulin resistance of FAS offspring. Findings suggest that high-dose perinatal FAS may promote insulin resistance and dyslipidemia and disrupt glucose metabolism possibly by depressing adiponectin expression. Although this is an animal model and the effects of the diets cannot be directly transposed to humans, this study provides indications of the possible adverse effects of FAS maternal diet on glucose metabolism in the offspring.

Where applicable, experiments conform with Society ethical requirements