Nesfatin-1, derived from nucleobindin 2, was recently identified as an anorexigenic signal peptide. However, its neural role in glucose homeostasis and insulin sensitivity is unknown. To evaluate the metabolic impact and underlying mechanisms of central nesfatin-1 signaling, we infused nesfatin-1 in the third cerebral ventricle of high-fat diet (HFD)–fed rats. The effects of central nesfatin-1 on glucose metabolism and changes in transcription factors and signaling pathways were assessed during euglycemic-hyperinsulinemic clamping. The infusion of nesfatin-1 into the third cerebral ventricle markedly inhibited hepatic glucose production (HGP), promoted muscle glucose uptake, and was accompanied by decreases in hepatic mRNA and protein expression and enzymatic activity of PEPCK in both standard diet- and HFD-fed rats. In addition, central nesfatin-1 increased insulin receptor (InsR)/insulin receptor substrate-1 (IRS-1)/AMP-dependent protein kinase (AMPK)/Akt kinase (Akt)/target of rapamycin complex (TORC) 2 phosphorylation and resulted in an increase in Fos immunoreactivity in the hypothalamic nuclei that mediate glucose homeostasis. Taken together, these results reveal what we believe to be a novel site of action of nesfatin-1 on HGP and the PEPCK/InsR/IRS-1/AMPK/Akt/TORC2 pathway and suggest that hypothalamic nesfatin-1 action through a neural-mediated pathway can contribute to increased peripheral and hepatic insulin sensitivity by decreasing gluconeogenesis and promoting peripheral glucose uptake in vivo.
The Asiatic rice borer, Chilo suppressalis (Walker) (Lepidoptera: Crambidae), is an important rice, Oryza sativa L., pest in China and difficult to control with conventional pest management. To develop and optimize integrated pest management strategies, efficient and economic artificial diet and rearing protocols are desirable. A new artificial diet based on soybean, Glycine max (L.) Merr., powder and fresh water bamboo, Zizania caduciflora (Turcz.) Hand.-Mazz, was formulated and rearing technique was developed. Fitness parameters including larval development, immature survival, pupal weight, pupation, adult emergence, egg hatchability, and oviposition were measured to evaluate the performance of C. suppressalis fed on the diet over 15 successive generations. C. suppressalis reared on the artificial diet showed better performance with shorter developmental stage, similar larval survival rate and fecundity, and heavier pupae compared with that fed on rice plants and fresh water bamboo. A positive correlation was observed between number of eggs laid per female and number of generations reared on the diet. Larval development time tended to be shortened with successive rearing on the artificial diet. These results indicated that C. suppressalis adapted well to the artificial diet and successive rearing conditions. The diet could serve as a viable alternative to natural host plants for consecutive rearing of the insect. In addition, the diet is inexpensive (US$1.5/1,000 g) and easy to make. The better preserve ability of the diet required only one diet replacement during the rearing process. The successful development of the diet and rearing technique provides a very useful tool for refining stem borer pest management techniques.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.