The SK/IK family of small and intermediate conductance calcium-activated potassium channels contains four members, SK1, SK2, SK3 and IK1, and is important for the regulation of a variety of neuronal and non-neuronal functions. In this study we have analysed the distribution of these channels in human tissues and their cellular localisation in samples of colon and corpus cavernosum. SK1 mRNA was detected almost exclusively in neuronal tissues. SK2 mRNA distribution was restricted but more widespread than SK1, and was detected in adrenal gland, brain, prostate, bladder, liver and heart. SK3 mRNA was detected in almost every tissue examined. It was highly expressed in brain and in smooth muscle-rich tissues including the clitoris and the corpus cavernosum, and expression in the corpus cavernosum was upregulated up to 5-fold in patients undergoing sex-change operations. IK1 mRNA was present in surface-rich, secretory and inflammatory cell-rich tissues, highest in the trachea, prostate, placenta and salivary glands. In detailed immunohistochemical studies of the colon and the corpus cavernosum, SK1-like immunoreactivity was observed in the enteric neurons. SK3-like immunoreactivity was observed strongly in smooth muscle and vascular endothelium. IK1-like immunoreactivity was mainly observed in inflammatory cells and enteric neurons of the colon, but absent in corpus cavernosum. These distinctive patterns of distribution suggest that these channels are likely to have different biological functions and could be specifically targeted for a number of human diseases, such as irritable bowel syndrome, hypertension and erectile dysfunction.

Most traditional cytotoxic anticancer agents ablate the rapidly dividing epithelium of the hair follicle and induce alopecia (hair loss). Inhibition of cyclin-dependent kinase 2 (CDK2), a positive regulator of eukaryotic cell cycle progression, may represent a therapeutic strategy for prevention of chemotherapy-induced alopecia (CIA) by arresting the cell cycle and reducing the sensitivity of the epithelium to many cell cycle-active antitumor agents. Potent small-molecule inhibitors of CDK2 were developed using structure-based methods. Topical application of these compounds in a neonatal rat model of CIA reduced hair loss at the site of application in 33 to 50% of the animals. Thus, inhibition of CDK2 represents a potentially useful approach for the prevention of CIA in cancer patients.

Bile acid sequestrants (BAS) have shown antidiabetic effects in both humans and animals but the underlying mechanism is not clear. In the present study, we evaluated cholestyramine in Zucker diabetic fatty (ZDF) rats. Although control ZDF rats had continuous increases in blood glucose and hemoglobin A1c (HbA1c) and serum glucose and a decrease in serum insulin throughout a 5-week study, the cholestyramine-treated ZDF rats showed a dose-dependent decrease and normalization in serum glucose and HbA1c. An oral glucose tolerance test showed a significant increase in glucose-stimulated glucagonlike peptide 1 (GLP-1), peptide YY (PYY), and insulin release in rats treated with cholestyramine. Quantitative analysis of gene expression indicated that cholestyramine treatment decreased farnesoid X receptor (FXR) activity in the liver and the intestine without liver X receptor (LXR) activation in the liver. Moreover, a combination of an FXR agonist with cholestyramine did not reduce the antihyperglycemic effect over cholestyramine alone, suggesting that the FXR-small heterodimer partner-LXR pathway was not required for the glycemic effects of cholestyramine. In summary, our results demonstrated that cholestyramine could completely reverse hyperglycemia in ZDF rats through improvements in insulin sensitivity and pancreatic ␤-cell function. Enhancement in GLP-1 and PYY secretion is an important mechanism for BAS-mediated antidiabetic efficacy.In the last decade, the traditional view of bile acids as essential players in dietary lipid absorption and cholesterol catabolism has changed. The discovery of bile acids as endogenous ligands for the nuclear receptor farnesoid X receptor (FXR; NR1H4) and the G-protein-coupled bile acid receptor (TGR5; GPBAR1) transformed bile acids from lipid absorption facilitator into autocrine, paracrine, and endocrine factors (Parks et al., 1999;Kawamata et al., 2003). In addition to negative feedback regulation of bile acid synthesis in the liver (Makishima et al., 1999), FXR influences many pathways involved in lipid and glucose metabolism (Lefebvre et al., 2009). FXR agonists have been shown to lower circulating cholesterol, triglycerides, and glucose and improve insulin sensitivity in multiple preclinical models (Duran-Sandoval et al., 2005;Stayrook et al., 2005;Cariou et al., 2006;Ma et al., 2006;Zhang et al., 2006). Similar to FXR, TGR5 mediates some hormonal actions of bile acids, including glucose metabolism. It has been demonstrated that bile acids promote glucagon-like-peptide 1 (GLP-1) secretion through TGR5 in STC-1, a murine enteroendocrine cell line (Katsuma et al., Article, publication date, and citation information can be found at

Retraction THE REPORT "PREVENTION OF CHEMOTHERAPYinduced alopecia in rats by CDK inhibitors" (1) harbors a fundamental inaccuracy. Although the chemical structure of compound 4 is correct as presented, we have not been able to reproduce the biological activity of this compound in the neonatal rat model of chemotherapy-induced alopecia. Thus, we must retract our results. We are continuing to investigate several compounds from another structural class of CDK inhibitors that block chemotherapyinduced alopecia in this model.

No abstract