Alterations in vasopressin and angiotensin II receptors and responses during culture of rat liver cells
| Autor: | John H. Exton, Guy Augert, B Bouscarel, Stephen J. Taylor |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Male
Receptors Vasopressin Vasopressin Angiotensin receptor medicine.medical_specialty Time Factors Biology chemistry.chemical_compound Internal medicine medicine Animals Phosphatidylinositol Molecular Biology Cells Cultured Receptors Angiotensin Phospholipase C Angiotensin II Liver cell Rats Inbred Strains Inositol trisphosphate Cell Biology Rats Arginine Vasopressin Endocrinology Liver chemistry Cell culture Calcium |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Molecular Cell Research. 1055:265-272 |
| ISSN: | 0167-4889 |
| DOI: | 10.1016/0167-4889(90)90042-c |
| Popis: | Vasopressin and angiotensin II binding and responses were studied in hepatocytes in primary culture for 4 h and 24 h. After 24 h of culture, angiotensin II was completely ineffective in elevating cytosolic [Ca2+], whereas the maximum [Ca2+] response to vasopressin was decreased by 66% and the sensitivity to the hormone was decreased approx. 20-fold compared with values after 4 h of culture. The dissociation constant (KD) for vasopressin binding to the cells was not significantly changed during 24 h of culture, but the Bmax was decreased by 63% compared with 4 h of culture. There was also no change in the KD for angiotensin II binding from 4 h to 24 h, but the Bmax was decreased by 90%. After 24 h of culture, there was no change in the plasma membrane concentration of phosphatidylinositol 4,5-bisphosphate or in the basal cell concentration of inositol trisphosphate. However, the trisphosphate did not increase with 100 nM angiotensin II and the response to 100 nM vasopressin was reduced by 66% compared with that at 4 h. The effect of guanosine 5′-(3-O-thiol) triphosphate on the polyphosphoinositide phospholipase C activity of liver cell plasma membranes was also measured. There was no decrease in the degree of stimulation of the phospholipase by this nucleotide after 24 h of culture. It is concluded that the loss of vasopressin and angiotensin II responses in cultured liver cells is due in part to changes in receptors and also in their coupling to a guanine nucleotide binding protein. |
| Databáze: | OpenAIRE |
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