No abstract

Affinity-purified bovine brain phosphatidylinositol 3-kinase (PI3-kinase) contains two major proteins of 85 and 110 kd. Amino acid sequence analysis and cDNA cloning reveals two related 85 kd proteins (p85 alpha and p85 beta), which both contain one SH3 and two SH2 regions (src homology regions). When expressed, these 85 kd proteins bind to and are substrates for tyrosine-phosphorylated receptor kinases and the polyoma virus middle-T antigen/pp60c-src complex, but lack PI3-kinase activity. However, an antiserum raised against p85 beta immunoprecipitates PI3-kinase activity. The active PI3-kinase complex containing p85 alpha or p85 beta and the 110 kd protein binds to PDGF but not EGF receptors. p85 alpha and p85 beta may mediate specific PI3-kinase interactions with a subset of tyrosine kinases.

Summary Fibroblast growth factor 21 (FGF21) is a hormone induced by various metabolic stresses, including ketogenic and high carbohydrate diets, that regulates energy homeostasis. In humans, SNPs in and around the FGF21 gene have been associated with macronutrient preference, including carbohydrate, fat and protein intake. Here we show that FGF21 administration markedly reduces sweet and alcohol preference in mice, and sweet preference in cynomolgus monkeys. In mice, these effects require the FGF21 co-receptor β-Klotho in the central nervous system and correlate with reductions in dopamine concentrations in the nucleus accumbens. Since analogs of FGF21 are currently undergoing clinical evaluation for the treatment of obesity and type 2 diabetes, our findings raise the possibility that FGF21 administration could affect nutrient preference and other reward behaviors in humans.

Development of microalbuminuria increases the risk for cardiovascular disease (CVD) in type 2 diabetes. The nature of this relationship is unclear but may involve arterial stiffness, an independent risk marker for CVD mortality. Aortic pulse wave velocity (Ao-PWV) and albumin creatinine ratio (ACR) were measured in 134 consecutive patients with type 2 diabetes without overt renal impairment (serum creatinine <150 mol/L). ACR ranged from 0.2 to 153 mg/mmol. Patients with raised ACR (>3 mg/mmol) had higher Ao-PWV, poorer diabetic control, and higher pulse pressure (PP) and systolic BP (SBP) (all P < 0.05) than those with normal ACR. The closest univariate associations of Ao-PWV were positively with age, duration of diabetes, SBP, PP, ACR, and insulin treatment and negatively with GFR and weight (all P < 0.01). In a multiple linear step-down regression analysis, the significant predictors of Ao-PWV were age, SBP or PP, duration of diabetes, gender, number of antihypertensive medications, and use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, which together explained 55% of the variance of Ao-PWV. When ACR was offered in place of arterial pressure to a separate model, ACR emerged as a significant predictor of Ao-PWV. After age adjustment, patients with lower, below median GFR had higher Ao-PWV than those with GFR above the median (P ‫؍‬ 0.043). In patients with type 2 diabetes without overt renal impairment, raised ACR is associated with higher Ao-PWV, a relationship most likely mediated by raised BP. The association of Ao-PWV with reduced GFR suggests that even modest renal dysfunction may affect the viscoelastic properties of large arteries.