RESUMEN
We have demonstrated structural differences between the mantle edge gland of young, adult and adult shell repairing snails. In vivo and in vitro, somatostatin-14 and somatostatin-immunoreactive substance (SSI) induce a juvenile status of the gland in adults and an activation of juvenile ones. These results suggest that they could regulate the growth and the repair of the shell and that the mantle edge gland might be considered as one of their tissue targets.
Asunto(s)
Caracoles Helix/efectos de los fármacos , Antagonistas de Hormonas/farmacología , Somatostatina/farmacología , Animales , Caracoles Helix/citología , Caracoles Helix/crecimiento & desarrollo , Técnicas In Vitro , Somatostatina/análogos & derivadosRESUMEN
The effect of four fibrate analogues (i.e. clofibrate, ciprofibrate, clobuzarit and 2,4-dichlorophenoxyacetic acid (2,4-D), an active herbicide molecule) were tested on the biogenesis of liver mitochondrial and peroxisomal proteins by rat in vivo treatment at 100 ppm for 26 weeks. The evaluations were done at different levels: somatic index, histochemistry electron microscopy, enzymatic activities on purified peroxisomes and mitochondria, polypeptides electrophoresis and immunolabeling, and finally mRNA hybridization with specific DNA probes. This work shows that the tested hypolipemic agents are strong peroxisomal proliferators especially ciprofibrate, while mitochondria are weakly affected. However, the four fibrates gave different effects, especially 2,4-D which modifies mitochondrial polypeptide pattern. Post-transcriptional study of mRNAs level shows a slight increase in catalase mRNA despite the potential of hypolipemic agents. The peroxisomal acyl-CoA oxidase mRNA content is enhanced with ciprofibrate treatment as well as mitochondrial R-3-hydroxybutyrate dehydrogenase (BDH) mRNA level. Finally, the dual action of ciprofibrate on content and on enzymatic activity of BDH (a lipid metabolism related enzyme) reveals that such a molecule may have differential regulatory effects (positive on gene transcription or mRNA stability and negative on catalytic enzyme activity).
Asunto(s)
Hipolipemiantes/farmacología , Hígado/efectos de los fármacos , Microcuerpos/efectos de los fármacos , Mitocondrias Hepáticas/efectos de los fármacos , Animales , Secuencia de Bases , Sondas de ADN , Hígado/metabolismo , Masculino , Microcuerpos/metabolismo , Mitocondrias Hepáticas/metabolismo , Datos de Secuencia Molecular , Biosíntesis de Proteínas , Ratas , Ratas Endogámicas F344RESUMEN
Immunocytology and radioimmunoassays demonstrate the presence of immunoreactive somatostatin-like (IR-SOM-LI) material in the tissues of young or adult snails Helix aspersa bred under short or long day in controlled artificial conditions. Neurosecretory cells in the circumoesophageal ganglia and in the digestive gland, small fibers in the hepatopancreas, and small granules in the mantle epithelial cells are immunoreactive toward antisomatostatin. In all experimented animals shell fractures induce variations of the IR-SOM-LI concentrations in all assayed tissues whatever the lighting conditions were underwent. These findings support the hypothesis that in Helix one or more substances related to the vertebrate tetradecapeptide is (are) involved in the repair processes but that the storage and the metabolism may be different during the biological cycle of the snails. These results are compared with those previously published using different gastropods and different methods.