Survival and differentiation of pituitary colony-forming cells in vivo.

Growth hormone (GH) deficiency is a significant clinical problem, since growth hormone is essential for the regulation of growth, metabolism, and the cardiovascular system. Stem and progenitor cells have been identified in many adult tissues. Recently, our laboratory identified a cell type within the adult pituitary gland with stem cell-like properties, which we have termed pituitary colony-forming cells (PCFCs).

A role for angiotensin-converting enzyme in the characterization, enrichment, and proliferation potential of adult murine pituitary colony-forming cells.

Recently, we described a rare cell type within the adult murine pituitary gland with progenitor cell hallmarks (PCFCs). PCFCs are contained exclusively within a subpopulation of cells that import fluorescent beta-Ala-Lys-Nepsilon-AMCA (7-amino-4-methylcoumarin-3-acetic acid). Herein, we investigate the utility of cell surface molecules angiotensin-converting enzyme (ACE) and stem cell antigen-1 (Sca-1) to further enrich for PCFCs.

Overexpression of glutathione peroxidase with two isoforms of superoxide dismutase protects mouse islets from oxidative injury and improves islet graft function.

Primary nonfunction of transplanted islets results in part from their sensitivity to reactive oxygen species (ROS) generated during the isolation and transplantation process. Our aim was to examine whether coexpression of antioxidant enzymes to detoxify multiple ROS increased the resistance of mouse islets to oxidative stress and improved the initial function of islet grafts. Islets from transgenic mice expressing combinations of human copper/zinc superoxide dismutase (SOD), extracellular SOD, and cellular glutathione peroxidase (Gpx-1) were subjected to oxidative stress in vitro.

Enhanced expression of glutathione peroxidase protects islet beta cells from hypoxia-reoxygenation.

The survival of pancreatic islet beta-cell xenografts and allografts may be affected by damaging reactive oxygen and nitrogen species generated during hypoxia-reoxygenation. Peroxynitrite, which is formed from superoxide and nitric oxide, appears to be an important mediator of beta-cell destruction. The intracellular antioxidant enzymes glutathione peroxidase-1 (Gpx-1) and copper-zinc superoxide dismutase (CuZn SOD) detoxify peroxynitrite and superoxide, respectively.

Detection and quantification of nitric oxide (NO) synthase-independent generation of NO.

Nitric oxide formation in ischemia-reperfusion injury can be identified and measured directly using EPR of nitroso-heme complexes comprising NO bound to either Mb or Hb-Fe2+. This article described the successful use of this method to detect and quantify the generation of NO formed independently of nitric oxide synthase in ischemia-reperfusion injury to skeletal muscle. The quantification of nitroso-heme complexes using EPR is recommended in ischemia-reperfusion studies of either skeletal or cardiac muscle that aim to characterize the role of nitric oxide.