Juan Miguel Ruiz-Albusac

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Although the brain has been considered an insulin-insensitive organ, recent reports on the location of insulin and its receptors in the brain have introduced new ways of considering this hormone responsible for several functions. The origin of insulin in the brain has been explained from peripheral or central sources, or both. Regardless of whether insulin(More)
Glucagon-like peptide-2 (GLP-2) is a potent intestinotrophic/satiety hormone that acts through a G protein-coupled receptor. To determine whether or not GLP-2 has any effect on cellular proliferation on neural cells, we examined the effects of this peptide on cultured astrocytes from rat cerebral cortex. The expression of the GLP-2 receptor gene in both(More)
Labeling with [3H]galactose was employed to isolate a glycosylphosphatidylinositol from rat hepatocytes which might be involved in the action of insulin. The polar head group of this glycosylphosphatidylinositol was generated by phosphodiesterase hydrolysis with a phosphatidylinositol-specific phospholipase C from Bacillus cereus. By Dowex AG1 x 8(More)
A phosphatidylinositol-glycan has been implicated in the mechanism of action of insulin. Some of the actions of insulin may be mediated by the generation of the polar head group of this phosphatidylinositol-glycan. Localisation of the insulin-sensitive phosphatidylinositol-glycan was investigated by reacting the glycophospholipid with the imidoester(More)
The aim of this work was to determine whether the stimulating effect of glucagon-like peptide (GLP)-2 on astrocyte proliferation could be reinforced by proliferating substances, including growth factors such as EGF, platelet-derived growth factor, insulin-like growth factor type I (IGF-I) or a hormone such as insulin. Both DNA synthesis and astrocyte(More)
Glycosyl phosphatidylinositols have been implicated in insulin signaling through their action as precursors of second messenger molecules in peripheral tissues. In the present study, cultured rat astrocytes were used to investigate whether glycosyl phosphatidylinositol might be involved in the mechanism of insulin signal transduction in neural cells. A(More)
We examined the effects of 25-OH-cholesterol on the growth of cultured rat astrocytes in the presence of lipoprotein-deficient serum (LPDS). 25-OH-cholesterol at 0.5-8 microM induced an increase in DNA synthesis as measured by [3H]thymidine incorporation into DNA, staining the cells with crystal violet, or counting the number of cells in different phases of(More)
We have investigated the topography of a glycosyl-phosphatidylinositol implicated in insulin action by a combination of two complementary methods: (a) chemical labelling with a non-permeable (isethionyl acetimidate) and a permeable (ethyl acetimidate) probe; and (b) enzymatic modifications with beta-galactosidase (EC 3.2.1.23) or(More)
Estrogen binding in the liver of pregnant rats has been studied. When the results are expressed in pmol/mg of protein there is a marked decrease in relation to control rats on 12th or 21st days of gestation. In spite of the liver weight increase on day 21, however, the binding capacity for estrogens in the whole liver is still lower than in controls. It is(More)
The in vitro transfer of free cholesterol (FC) between human serum lipoproteins in the absence of lecithin:cholesterol acyltransferase (LCAT) activity has been examined. The results show that the amount of FC that the high-density lipoprotein (HDL) and lipoprotein-deficient serum (LDS) fractions were able to capture from low-density lipoproteins (LDL) and(More)