HORMONE REGULATION OF PHOSPHOINOSITIDE BREAKDOWN

  • Litosch, Irene, (PI)

Project: Research project

Description

The proposed studies are designed to investigate the regulation of
phosphoinositide breakdown by hormones in a cell-free system from the
blowfly salivary gland. Phosphoinositide breakdown has been linked to a
receptor mechanism, distinct from the cyclic AMP system, involved in the
elevation of cytosolic Ca2+. The system to be used in these studies, the
salivary gland of the blowfly, Calliphora erythrocephala, selectively
incorporates (3H)ubisutik and (32P)Pi into the pool of phosphoinositides
involved in hormone action. Using a membrane fraction, obtained from
salivary glands prelabeled with (3H)inositol, it is possible to demonstrate
5-hydroxytryptamine-stimulated production of inositol phosphates derived
from phosphoinositide breakdown. Hormone-stimulated breakdown in the
cell-free system is rapid and is mediated through a phospholipase active at
physiological pH. The relationship between phosphatidylinositol and the
polyphosphoinositides in the cell-free system has not been defined. The
isolated membrane fraction will be used for the biochemical
characterization of the phospholipases involved in hormone-stimulated
phosphoinositide breakdown, the mechanism by which hormone stimulates
phosphoinositide breakdown, the nature of the active pool of
phosphoinositides involved in hormone action and the metabolic
interrelationship between phosphatidylinositol and the
polyphosphoinositides.
StatusFinished
Effective start/end date9/20/858/31/88

Funding

  • National Institutes of Health

Fingerprint

hormones
cell free system
phosphatidylinositols
Calliphora vicina
inositol phosphates
Calliphoridae
cyclic AMP
salivary glands
serotonin
calcium
phospholipases

ASJC

  • Medicine(all)