No abstract

Mg deficiency induces various metabolic disturbances including glucose metabolism in the liver. However, no comprehensive information is currently available on the metabolic pathways affected by Mg deficiency. The present study examined metabolite content in the liver of Mg-deficient rats using a metabolomic analysis. In this study, 4-week-old, male Sprague-Dawley rats were fed a control diet or a Mg-deficient diet for 8 weeks. The metabolomic analysis identified 105 metabolites in the liver, and significant differences were observed in the hepatic contents for thirty-three metabolites between the two groups. An analysis by MetaboAnalyst, a web-based metabolome data analysis tool, indicated that the Mg deficiency affected taurine/hypotaurine metabolism, methionine metabolism and glycine/serine/threonine metabolism; taurine, hypotaurine, glycine, serine and threonine contents were increased by Mg deficiency, whereas the amounts of 2-ketobutyric acid (a metabolite produced by the catabolism of cystathionine or threonine) and 5'-methylthioadenosine (a metabolite involved in spermidine synthesis) were decreased. The amount of glucose 6-phosphate, a hub metabolite of glycolysis/gluconeogenesis and the pentose phosphate pathway, was significantly decreased in Mg-deficient rats. Mg deficiency also decreased metabolite contents from the citric acid cycle, including citric acid, fumaric acid and malic acid. Aberrant metabolism may be related to the allosteric regulation of enzymes; the mRNA levels of enzymes were generally similar between the two groups. The present study suggests that the Mg deficiency-mediated modulation of hepatic metabolism is as yet uncharacterised.

Expression of uncoupling protein (Ucp) 2 but not Ucp3 in subcutaneous fat was significantly higher in cattle fed the concentrate diet than in those fed the roughage diet. Ucp2 expression in mesenteric fat was higher in cattle fed the vitamin A-deficient diet than in those fed the control diet.

a b s t r a c tThe BMP pathway positively regulates murine brown adipogenesis. We herein examined the mRNA levels of BMPs and activin βB as well as receptors for the BMP pathway in the adipose tissues of cattle fed diets with a differential ratio of concentrate to roughage or a vitamin A-deficient diet. The expression of activin βB was significantly increased in the subcutaneous fat depot of animals fed the concentrate diet, while the vitamin A-deficient diet significantly increased the expression of BMP4 in the mesenteric fat depot. The expression of receptors for the BMP pathway, ALK2, ALK3, ActRIIA, and BMPR2, showed a similar pattern to that of BMP4 and activin βB in response to the dietary treatments. The results of the present study demonstrated that diet modulated the expression of components of the BMP pathway and may be responsible for the regulatory expression of brown/beige adipocyte-related genes in the adipose tissues of cattle.