Abstract
In blowfly salivary glands, 5-hydroxytryptamine stimulated a rapid and sustained loss of [3H]inositol, [32P]phosphatidylinositol, phosphatidylinositol 4-phosphate, and phosphatidylinositol 4,5-bisphosphate. There was a corresponding increase in labeled inositol phosphates. In the absence of Ca2+, 5-hydroxytryptamine stimulated a rapid but transient loss of labeled phosphatidylinositol 4,5-bisphosphate. By 5 min, the amount of labeled phosphatidylinositol 4,5-bisphosphate recovered to control values. The divalent ionophore A23187 stimulated loss of labeled phosphatidylinositol 4,5-bisphosphate and increased the amount of labeled phosphatidylinositol. In homogenates, Ca2+ stimulated phosphatidylinositol 4,5-bisphosphate breakdown but not phosphatidylinositol breakdown. These results suggest that hormone-stimulated breakdown of labeled phosphatidylinositol and phosphatidylinositol 4,5-bisphosphate occurs through a phospholipase C and - is relatively independent of extracellular Ca2+. There is also Ca2+-activated conversion of phosphatidylinositol 4,5-bisphosphate to phosphatidylinositol.
Original language | English |
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Journal | American Journal of Physiology - Cell Physiology |
Volume | 15 |
Issue number | 1 |
State | Published - Jan 1 1984 |
Externally published | Yes |
ASJC Scopus subject areas
- Cell Biology
- Clinical Biochemistry
- Physiology