Melittin stimulates phosphoinositide hydrolysis and placental lactogen release: Arachidonic acid as a link between phospholipase A sub 2 and phospholipase C signal-transduction pathways

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Life Sciences; (USA)

DOI:https://doi.org/10.1016/0024-3205(91)90166-9· OSTI ID:5801976

Zeitler, P; Handwerger, S ^[1]; Wu, Y Q ^[2]

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1. Univ. of Cincinnati College of Medicine, OH (USA)
2. Duke Univ. Medical Center, Durham, NC (USA)

Previous investigations from this laboratory have implicated both phospholipase A{sub 2} and phospholipase C in the regulation of human placental lactogen release from human trophoblast. To study further the role of endogenous phospholipase A{sub 2} and the relationship between phospholipase A{sub 2} activation and phosphoinositide metabolism, the authors examined hPL and ({sup 3}H)-inositol release from trophoblast cells in response to agents that stimulate or inhibit the endogenous enzyme. Melittin stimulated rapid, dose-dependent, and reversible increases in the release of hPL, prostaglandin E, and ({sup 3}H)-inositol. Mepacrine inhibited this stimulation. However, mepacrine had no effect on the stimulation of hPL and ({sup 3}H)-inositol release by exogenous arachidonic acid (AA). These results indicate that the stimulation by melittin of phosphoionsitide metabolism and hPL release is mediated by initial activation of phospholipase A{sub 2}. Furthermore, the results support the possibility that AA, released as a consequence of phospholipase A{sub 2} activation, can act as a second messenger linking the two phospholipase pathways.

• OSTI ID: 5801976
• Journal Information: Life Sciences; (USA), Journal Name: Life Sciences; (USA) Vol. 48:21; ISSN 0024-3205; ISSN LIFSA
• Country of Publication: United States
• Language: English

Related Subjects

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550501 -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANIMALS
ARACHIDONIC ACID
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL PATHWAYS
CARBOXYLESTERASES
CARBOXYLIC ACIDS
DOSE-RESPONSE RELATIONSHIPS
ENZYME ACTIVITY
ENZYME INHIBITORS
ENZYMES
ESTERASES
ESTERS
FETAL MEMBRANES
HORMONES
HYDROGEN COMPOUNDS
HYDROLASES
ISOTOPE APPLICATIONS
KINETICS
LACTOGENS
LIPASES
LIPIDS
MAMMALS
MAN
MEMBRANES
METABOLISM
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PEPTIDES
PHOSPHOLIPIDS
PLACENTA
POLYPEPTIDES
PRIMATES
PROSTAGLANDINS
PROTEINS
REACTION KINETICS
SECRETION
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES