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Fibroblast growth factor (FGF)-21 recently has been identified as a potent glucose regulator with potential to become a therapeutic approach for treatment of type 2 diabetes mellitus. However, the mechanism of glucose regulation by the molecule is not fully understood. The objective of this paper was to determine the effects of FGF-21 on glucose uptake and its molecular mechanism. In this study, 3T3-L1 adipocytes and pre-adipocytes were used to study the correlation between glucose uptake stimulated by FGF-21 and glucose transporter (GLUT)-1 expression and translocation. The cells were stimulated by FGF-21, insulin or combination of both, and the glucose consumption of the cells was detected by the method of glucose oxidizes/peroxides (GOD-POD); the mRNA expression of GLUT1 was detected by real-time polymerase chain reaction (PCR) with specific primers; GLUT1 translocation was examined by Immuno-fluorescence. The results showed that FGF-21 dramatically stimulated glucose uptake by differentiated adipocytes, but that it had no effect on pre-adipocytes. Effects on GLUT1 expression and regulation likely contributed to this effect, since GLUT1 was expressed and translocated to the cell membrane of the adipocytes upon stimulation by FGF-21. In addition, FGF-21 had a synergistic effect with insulin on glucose uptake by adipocytes, further suggesting that the effect with FGF-21 was not mediated via GLUT4. This study provides evidence for stimulation of GLUT1-, mediated uptake of glucose into adipocytes by FGF-21, and clearly demonstrates dynamic regulation of GLUT1 by FGF-21 stimulation. Key words: Fibroblast growth factor (FGF)-21, adipocytes, glucose transporter (GLUT)-1, translocation.

Synonymous codons are not used randomly. Rather, some codons are used more frequently than others. Investigating codon usage bias is essential to the understanding of viral evolution. However the factors shaping synonymous codon usage bias and nucleotide composition in animal viruses have been studied only to a limited extent. In our study, using the 19 complete CDS sequences of Spike (S) genes of porcine epidemic diarrhea virus (PEDV), we analyzed synonymous codon usage bias. The relative synonymous codon usage (RSCU) was used to estimate codon usage variation in each gene, and the results indicated that preferentially used codons were A-ended, G-ended, and U-ended codons. Effective number of codons (ENC) values varies from 48.15 to 49.52, which suggested that the codon usage bias in PEDV S genes was very slightly. Correspondence analysis (COA) was further performed to study the major trend in codon usage variation, and the plot of ENC values against GC3s (at synonymous third codon position) revealed that mutational pressure rather than translational selection was the main factor determining the codon usage bias in PEDV S genes. Moreover, correlation analysis indicated that aromaticity and hydrophobicity of S genes also influenced the codon usage variation in a minor way. Our study provides the most comprehensive analysis to date of PEDV S genes’ codon usage patterns and provides a basic understanding of the mechanisms for codon usage bias. Key words: Porcine epidemic diarrhea virus, Spike gene, relative synonymous codon usage, effective number of codons, correspondence analysis, correlation analysis.