Alpha 1-adrenergic inositol trisphosphate production in brown adipocytes is Na+ dependent.
1987 (English)In: Biochimica et Biophysica Acta, ISSN 0006-3002, Vol. 930, no 3, 438-445 p.Article in journal (Refereed) Published
In order to investigate the ionic requirements for inositol trisphosphate production, brown adipocytes were prelabelled with myo-[3H]inositol and the formation of inositol trisphosphates and inositol bisphosphates as a consequence of alpha 1-adrenergic stimulation was monitored. Omission of Ca2+ from the incubation medium diminished the norepinephrine-induced increase in inositol trisphosphate levels, but it would seem that this reduction can be fully accounted for by a decreased level of the 'inactive' isomer inositol 1,3,4-trisphosphate. Omission of Na+ fully abolished the norepinephrine-induced inositol trisphosphate response. However, it was observed that the presence of Li+ in the incubation medium could fully reconstitute the ability of the cells to yield the early response of inositol trisphosphate production; Li+ could, however, not substitute for Na+ in the entire alpha 1-adrenergic cellular pathway. It was concluded that the Na+-dependent step is found in the coupling mechanism between the alpha 1-receptor and the activation of the phosphodiesterase responsible for inositol trisphosphate production. Thus, all events in the alpha 1-adrenergic pathway which are consequences of IP3 production should appear to be Na+-dependent in these cells.
Place, publisher, year, edition, pages
1987. Vol. 930, no 3, 438-445 p.
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:kau:diva-29819PubMedID: 2820506OAI: oai:DiVA.org:kau-29819DiVA: diva2:657597