Growth hormone regulates the distribution of L-type calcium channels in rat adipocyte membranes
| Autor: | G. Peter Frick, S. Gaur, H. Maurice Goodman, Mary E. Morton |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Male
Dihydropyridines medicine.medical_specialty Calcium Channels L-Type Physiology chemistry.chemical_element Biology Calcium Basal (phylogenetics) chemistry.chemical_compound Cytosol Microsomes Internal medicine Adipocyte Adipocytes medicine Animals Distribution (pharmacology) L-type calcium channel Cells Cultured Epididymis Cell Membrane Rats Inbred Strains Cell Biology Rats Kinetics Endocrinology Membrane Adipose Tissue chemistry Growth Hormone Calcium Channels Isradipine Cell fractionation |
| Zdroj: | American Journal of Physiology-Cell Physiology. 275:C505-C514 |
| ISSN: | 1522-1563 0363-6143 |
| Popis: | Earlier studies demonstrated that deprivation of growth hormone (GH) for ≥3 h decreased basal and maximally stimulated cytosolic Ca2+in rat adipocytes and suggested that membrane Ca2+channels might be decreased. Measurement of L-type Ca2+channels in purified plasma membranes by immunoassay or dihydropyridine binding indicated a two- to fourfold decrease after 3 h of incubation without GH. No such decrease was seen in unfractionated adipocyte membrane preparations. The decrease in plasma membrane channel content was largely accounted for by redistribution of channels to a light microsomal membrane fraction. Immunoassay of α1-, α2/δ-, and β-channel subunits in membrane fractions indicated that the channels redistributed as intact complexes. Addition of GH during the 1st h of incubation prevented channel redistribution, and addition of GH after 3 h restored channel distribution to the GH-replete state of freshly isolated adipocytes. The studies suggest that GH may regulate the abundance of Ca2+channels in the adipocyte plasma membrane and thereby modulate sensitivity to signals, the expression of which is Ca2+dependent. |
| Databáze: | OpenAIRE |
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