RESUMEN
Knowledge about the specification of the germ line in penaeid shrimp would allow development of techniques to control germ cell formation and/or fate to produce reproductively sterile shrimp for genetic copyright purposes. Recent studies have traced the localization of an RNA-enriched intracellular body (ICB) in the putative germ line of four penaeid shrimp species. It is hypothesized that the ICB may serve as a putative germ granule and marker of germ line fate. In this study semi-thin and ultra-thin sections of Marsupenaeus japonicus embryos were prepared, and the dimensions and ultrastructure of the ICB was examined at different stages of embryogenesis. The ICB was an aggregation of electron dense granules, small vesicles and multi-vesicular bodies (MVBs), similar to germ granules from other species. Lamellar membranes and mitochondria were localized at the periphery of the ICB. Using fluorescence microscopy, microtubules were also observed between the centrosome and the ICB. The localization of the ICB in the D lineage and putative germ cell line, the enrichment of RNA in the ICB, and the ultrastructural similarities to other germ granules characterized in this study support the hypothesis that the ICB contains germ granules.
Asunto(s)
Penaeidae/embriología , Penaeidae/ultraestructura , Animales , Gránulos Citoplasmáticos/metabolismo , Gránulos Citoplasmáticos/ultraestructura , Células Germinativas/crecimiento & desarrollo , Células Germinativas/ultraestructura , Microscopía Confocal , Microscopía Electrónica de Transmisión , Microscopía Fluorescente , Cuerpos Multivesiculares/metabolismo , Cuerpos Multivesiculares/ultraestructuraRESUMEN
GR43175 is a selective 5-HT 1-like receptor agonist which is effective in the acute treatment of migraine. Rats and dogs were dosed intravenously (iv) and orally (po) with 1 mg 14C-GR43175 base (as succinate salt)/kg bodyweight. GR43175 is rapidly absorbed after oral dosing. In dog, 95-100% of the dose is absorbed, but less (25-30%) is absorbed by the rat. The bioavailability is greater than 54% in dog, but lower in rat. Except for the CNS, drug-related material is widely distributed after iv dosing, but is mainly concentrated in the gastrointestinal tract and excretory organs after oral dosing. GR43175 is eliminated from plasma by a combination of renal and metabolic clearance. Some first-pass metabolism occurs in both species. In dog the major route of excretion is in urine (78-83% of the dose) after either route of administration. In rat, urine is also the major route of excretion (71%) after iv dosing. After oral dosing to the rat the major route of excretion is in the faeces (83%). GR43175 is extensively metabolized, after either route of administration, in both species. GR49336, the indole acetic acid derivative of GR43175, is the major metabolite in dog and a major metabolite in rat.
Asunto(s)
Indoles/farmacocinética , Sulfonamidas/farmacocinética , Administración Oral , Animales , Autorradiografía , Perros , Indoles/administración & dosificación , Inyecciones Intravenosas , Ratas , Sulfonamidas/administración & dosificación , Sumatriptán , Distribución TisularRESUMEN
The distribution in rats of two radiolabelled derivatives of the potent pepsin inhibitor, pepstatin A, has been monitored by whole-body autoradiography. There was a very poor absorption of pepstatinyl-[14C]glycine and N-[3H]acetylstatine across the gastric and intestinal mucosae after oral administration. Both inhibitors were rapidly cleared from the blood by the liver and kidneys after intravenous administration. Neither inhibitor was localised in the gastric mucosa at a concentration that could be expected to be effective in inhibiting intracellular pepsin activity.