Effect of growth hormone-releasing factor on phosphoinositide hydrolysis in somatotrophs
| Autor: | J. Kraicer, M.B. French, B. C. Moor, B.T. Lussier |
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| Rok vydání: | 1990 |
| Předmět: |
Male
medicine.medical_specialty Somatotropic cell Inositol Phosphates Biology Growth Hormone-Releasing Hormone Phosphatidylinositols Biochemistry Second Messenger Systems chemistry.chemical_compound Endocrinology Pituitary Gland Anterior Internal medicine medicine Animals Inositol Phosphatidylinositol Inositol phosphate Molecular Biology Cells Cultured chemistry.chemical_classification Phospholipase C Phosphoric Diester Hydrolases Hydrolysis Phosphatidylinositol Diacylglycerol-Lyase Phosphatidylinositol diacylglycerol-lyase Inositol trisphosphate Rats Enzyme Activation chemistry Second messenger system |
| Zdroj: | Molecular and cellular endocrinology. 72(3) |
| ISSN: | 0303-7207 |
| Popis: | We studied the role of the phosphatidylinositol system in the action of growth hormone-releasing factor (GRF). We asked whether GRF stimulates the activity of phospholipase C by determining GRF-induced changes in 32P labeling of the individual phosphoinositides and inositol phosphates in purified rat somatotrophs. The somatotrophs were challenged with GRF (10(-7)M) for 0.33, 1, 3, 10, 30, and 90 min. GRF did not significantly or consistently alter 32P incorporation into phosphatidylinositol bisphosphate (PIP2), phosphatidylinositol monophosphate (PIP), or phosphatidylinositol (PI), except for a small reduction in PIP labeling at 90 min. In general the level of 32P incorporation into the inositol phosphates did not increase but instead decreased with GRF. There was a small but significant reduction of labeling of inositol trisphosphate (IP3) at 90 min of GRF incubation. There were also small but significant decreases in 32P incorporation into inositol bisphosphate (IP2) at 0.33, 3, and 30 min. GRF did not significantly alter 32P labeling of inositol monophosphate (IP). These results indicate that GRF does not stimulate phospholipase C activity in somatotrophs. We conclude that the phosphatidylinositol second messenger system does not play an essential role in the action of GRF. |
| Databáze: | OpenAIRE |
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