The effects of vitamin D3 on lipogenesis in the liver and adipose tissue of pregnant rats

Obesity is a worldwide individual and public health issue, and contributes to the development of numerous chronic diseases. In particular, maternal obesity has harmful effects on both the mother and child during and after pregnancy. The digestion and metabolism of food are controlled by endocrine factors, including insulin, glucagon and estrogen. These hormonal factors are differentially regulated during pregnancy due to the specialized hormonal environment during this period. In the present study, we examined the effects of 1,25-dihydroxyvitamin D3 (VD3), an active hormonal form of nutritional vitamin D3, on lipid metabolism in pregnant rats. The body weight of rats treated with VD3 was significantly reduced compared to that of the rats in the control group. In addition, histological analysis demonstrated that the amount of fat stored in adipocytes was reduced by treatment with VD3. To determine the role of VD3 in lipid metabolism, the expression levels of lipid metabolism-associated genes were measured in the rat adipose tissue and liver. VD3 negatively regulated the expression of various lipogenic genes, including fatty acid synthase (FAS), stearoyl-CoA desaturase 1 (SCD1) and acetyl-CoA carboxylase 1 (ACC1), in both the adipose tissue and liver. However, the regulators of lipogenic enzymes such as, sterol regulatory element-binding protein-1c (SREBP-1c), peroxisome proliferator-activated receptor-gamma (PPAR-gamma) and insulin-induced gene 2 (INSIG2) were differentially regulated by VD3 in a tissue-specific manner. On the whole, these findings suggest that VD3 regulates lipid metabolism and deposition in the liver and adipose tissue, and thereby reduces fat in pregnant animals, as well as body weight. Our results suggest that the alteration of lipogenesis through the administration of VD3 may help to reduce excessive weight gain during pregnancy and prevent obesity-related pregnancy complications such as pre-eclampsia, gestational diabetes, hypertension and issues with labor.