Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The actions of insulin, vanadate (V) and hydrogen peroxide (H2O2) on IGF-II binding and insulin receptor tyrosine kinase activity were studied in rat adipocytes. Incubating adipocytes with a combination of V plus H2O2 resulted in a potent synergistic effect on both the increase in IGF-II binding and the activation of the insulin receptor kinase. Catalase, which removes H2O2, abolished this synergism if added at the time of mixing of V plus H2O2 but not if added 10 min. later, suggesting that the formation of peroxide(s) of vanadate generated a potent insulin mimicker. The data support a critical role for the insulin receptor kinase in insulin action. The novel insulin-mimetic compound, a presumed peroxide of vanadate, could prove useful for investigating insulin action and may be valuable for treating insulin resistance.
 ...
PMID:Peroxide(s) of vanadium: a novel and potent insulin-mimetic agent which activates the insulin receptor kinase. 363 68

We have studied the survival requirements of osteoblasts to test the hypothesis that osteoblasts undergo programmed cell death (PCD) or apoptosis unless they are continuously signalled by other cells not to do so. Osteoblasts survived for 6 days in culture at high cell density in the absence of other cell types, serum or exogenous proteins, but they died with the morphological features of apoptosis in these conditions at low cell density. Osteoblast survival was enhanced during the first 2 days of culture by the addition of the sulphydryl compound, cysteine to the culture medium which was converted intracellularly to the antioxidant glutathione. Catalase, an enzyme decomposing hydrogen peroxide, also protected the cells, whereas superoxide dismutase had no effect. Therefore, osteoblasts in culture are sensitive to toxic compounds derived from molecular oxygen, i.e. hydroxyl radicals or hydrogen peroxide spontaneously generated in CMRL medium containing ascorbate and ferrous ions. Conditioned medium from high density cultures prevented osteoblast apoptosis in low density cultures, as long as antioxidants were also present. The enhancing effect of conditioned medium on osteoblast survival was prevented by neutralizing antibodies to insulin-like growth factor-I (IGF-I) and IGF-II but not by antibodies to either platelet-derived growth factor (PDGF) or basic fibroblast growth factor (bFGF). These results suggest that in addition to regulating cell growth and differentiation, IGF-I and IGF-II also function as survival factors for osteoblasts. Our data also indicate that antioxidants are required for osteoblast survival and that they enhance growth factor mediated osteoblast survival.
 ...
PMID:Autocrine signals promote osteoblast survival in culture. 1111 65