Repetitive transient rises in cytoplasmic free calcium in hormone-stimulated hepatocytes
| Autor: | Peter H. Cobbold, N. M. Woods, K. S. R. Cuthbertson |
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| Rok vydání: | 1986 |
| Předmět: |
Male
medicine.medical_specialty Cytoplasm Glycogenolysis Aequorin chemistry.chemical_element Peptide hormone Calcium In Vitro Techniques Calcium in biology chemistry.chemical_compound Phenylephrine Internal medicine medicine Animals Phosphatidylinositol Receptor Phentolamine Multidisciplinary biology Inositol trisphosphate Rats Kinetics Endocrinology chemistry Liver biology.protein |
| Zdroj: | Nature. 319(6054) |
| ISSN: | 0028-0836 |
| Popis: | In the stressed animal, the vasoactive hormones vasopressin and angiotensin-II and the neurotransmitter noradrenaline induce liver cells to release glucose from glycogen. The intracellular signal that links the cell-surface receptors for noradrenaline (alpha 1) and vasoactive peptides to activation of glycogenolysis is known to be a rise in the cytoplasmic concentration of free calcium ions (free Ca). The receptors for these agonists induce the hydrolysis of phosphatidylinositol 4,5-bisphosphate, a minor plasmalemma lipid, to produce inositol trisphosphate and diacylglycerol. Inositol trisphosphate has been shown to mobilize intracellular calcium in hepatocytes. We show here, by means of aequorin measurements in single, isolated rat hepatocytes, that the free Ca response to these agonists consists of a series of transients. Each transient rose within 3 s to a peak free Ca of at least 600 nM and had a duration of approximately 7 s. The transients were repeated at intervals of 0.3-4 min, depending on agonist concentration. Between transients, free Ca returned to the resting level of approximately 200 nM. Clearly, the mechanisms controlling free Ca in hepatocytes are more complex than hitherto suspected. |
| Databáze: | OpenAIRE |
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