Growth hormone internalization in mitochondria decreases respiratory chain activity.

Growth hormone (GH) is a signaling molecule regulating cell proliferation, differentiation and metabolism via activation of specific cell surface receptors and subsequent triggering of signal transduction pathways. This is associated with GH/GH receptor internalization and accumulation of GH in several subcellular compartments, including mitochondria. To assess the functional relevance of such mitochondrial accumulation, we first confirmed the occurrence of mitochondrial GH uptake ex vivo as early as 10 min after (125)I-GH injection to the rats.

Expression and putative role of lactoseries carbohydrates present on NCAM in the rat primary olfactory pathway.

Primary olfactory neurons project axons from the olfactory neuroepithelium lining the nasal cavity to the olfactory bulb in the brain. These axons grow within large mixed bundles in the olfactory nerve and then sort out into homotypic fascicles in the nerve fiber layer of the olfactory bulb before terminating in topographically fixed glomeruli. Carbohydrates expressed on the cell surface have been implicated in axon sorting within the nerve fiber layer.

Expression of galectin 4 in the rat small intestine during postnatal development.

We determined the expression of an endogenous lectin, galectin 4, in the rat small intestine during postnatal development. The mRNA levels of galectin 4 did not change significantly between birth and adulthood. In contrast, the protein was present at higher levels after than before weaning, and the potential ligands for galectin 4 were more highly represented in the enterocyte microvilli of weaned than of suckling rats.

Expression and localization of galectin 4 in rat stomach during postnatal development.

Galectins are lectins implicated in cell-cell or cell-matrix adhesion, cell growth, the cell cycle, transcription processes, and apoptosis, and some of them are differentially regulated during pre- or post-natal development. The purpose of the present study was to determine whether the expression of galectin 4 is relevant to developmental processes during postnatal development in the rat stomach. Galectin 4 expression in the rat gastric mucosa, between birth and adulthood, was studied at the protein and mRNA levels by western and northern blotting, respectively.

Regulation of the intestinal glycoprotein glycosylation during postnatal development: role of hormonal and nutritional factors.

This review focuses on the regulation of the glycoprotein glycosylation process in small intestine and colon during postnatal development. Glycoproteins play a prominent part in intestine as mucins secreted by the goblet cells and as molecules of biological interest largely present in the microvillus membrane of the enterocytes (digestive enzymes, transporters). The age-related changes in the intestinal glycosylation control the quality of glycan chains of glycoproteins.

Glucocorticoid-induced maturation of glycoprotein galactosylation and fucosylation processes in the rat small intestine.

We determined the role of glucocorticoids in the maturation of glycoprotein galactosylation and fucosylation processes in the rat small intestine during postnatal development. Treatment of suckling rats with hydrocortisone (HC) increased activities of an O-glycan: galactosyltransferase, and of an alpha-1,2-fucosyltransferase, through transcriptional regulation of the FTB gene. The activities of a fucosyltransferase inhibitor and of the enzymes responsible for the synthesis and degradation of GDP-fucose were unaffected by the treatment, whereas a fall in the activity of alpha-L-fucosidase was observed.

Polyamine participation in the maturation of glycoprotein fucosylation, but not sialylation, in rat small intestine.

The aim of this study was to determine the role of polyamines in the diet-related maturation of the intestinal glycoprotein glycosylation during postnatal development in the rat. The activity of alpha-2,6-sialyltransferase and the sialylated forms of glycoproteins in the intestinal brush-border membranes were found to decrease considerably after weaning, in parallel with the intestinal level of putrescine. By contrast, the activity of alpha-1,2-fucosyltransferases, the mRNA levels for two alpha-1,2-fucosyltransferase genes, FTA and FTB, and the fucosylated forms of glycoproteins all increased after weaning, in parallel with the levels of spermidine and spermine.