Glucagon stimulation of ruthenium red-insensitive calcium ion transport in developing rat liver
| Autor: | F L Bygrave, P H Reinhart |
|---|---|
| Rok vydání: | 1981 |
| Předmět: |
History
medicine.medical_specialty Ruthenium red Phosphodiesterase Inhibitors Calcium ion transport Biology Glucagon Ruthenium Education chemistry.chemical_compound Internal medicine medicine Animals Endoplasmic reticulum Vesicle Biological Transport Ruthenium Red Stimulation Chemical Rats Computer Science Applications Endocrinology Bucladesine Liver chemistry Microsome Calcium Intracellular Subcellular Fractions Research Article Hormone |
| Zdroj: | Biochemical Journal. 194:541-549 |
| ISSN: | 0306-3283 |
| DOI: | 10.1042/bj1940541 |
| Popis: | The maturation of glucagon-stimulated Ruthenium Red-insensitive Ca2+-transport activity was determined in livers of rats ranging in age from 5 days preterm to 10 weeks of adult life. Previous indications are that this activity is confined to vesicles derived mainly from the endoplasmic reticulum. Perinatal-rat liver contains near-adult values of Ruthenium Red-insensitive Ca2+-transport activity, and exhibits large transient increases in the rate of this activity at two stages of development, immediately after birth, and at 2-5 days after birth. The administration of glucagon to foetal rats, at developmental stages after 19.5 days of gestation (2.5 days before birth), results in a large stable increase (greater than 100%) of Ca2+-transport activity in a subsequently isolated ‘heavy’ microsomal fraction. That this fraction was enriched in vesicles derived from the rough endoplasmic reticulum was indicated by both an electron-microscopic examination and a marker-enzyme analysis of the subcellular fractions. The administration of glucagon into newborn animals only hours old does not enhance further the initial rate of Ca2+-transport activity, and from day 1 to 10 weeks after birth the administration of the hormone results in the moderate enhancement of Ca2+ transport. Experiments with cyclic AMP and inhibitors of phosphodiesterase activity suggest that cyclic AMP plays a key role in the enhancement by glucagon of Ruthenium Red-insensitive Ca2+ transport, and arguments are presented that this transport system has an important metabolic role in the redistribution of intracellular Ca2+ in liver tissue. |
| Databáze: | OpenAIRE |
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