ATP and adenosine stimulate phosphatidylcholine secretion in type II pneumocytes by different mechanisms

Conference · Fri May 01 04:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5629813

Rooney, S A; Gilfillan, A M

ATP and adenosine (A) stimulate phosphatidylcholine (PC) secretion in type II cells. ATP stimulates approx. 5-fold while A stimulates only 2-fold. There is evidence that the effect of A is mediated by the A/sub 2/ subtype of the P/sub 1/ receptor and involves an increase in intracellular cAMP. The aim of this study was to determine if ATP and A stimulate PC secretion by different mechanisms. Cells isolated from the adult rat were incubated with /sup 3/H-choline for 20 h, transferred to fresh medium and incubated with the test compounds for 90 min when /sup 3/H-PC in the cells and medium was measured. At the optimal concentration (1 mM), ATP increased secretion by 4.5-fold from 0.90 +/- 0.04% of total /sup 3/H-PC in the medium to 4.08 +/- 0.39% (n=9; p < 0.001). The protein kinase C activator, 12-0-tetra-decanoyl-13-phorbol acetate, similarly increased PC secretion 3.6-fold from 0.97 +/- 0.06 to 3.47 +/- 0.53% (n=4; P < 0.02). The effect of ATP (0.1 mM) was reduced over 50% by prior incubation with the P/sub 2/ desensitizing agent ..cap alpha.., ..beta..-methylene-ATP (0.1 mM) but only 20% by the P/sub 1/ antagonist 8-phenyltheophylline which reduced the effect of A by 50%. Terbutaline doubled the rate of PC secretion and this effect was additive to that of ATP but not to that of A. In contrast to A, which increased the level of intracellular cAMP 12-fold, ATP only produced a 3-fold increase in cAMP from 0.23 +/- 0.05 to 0.72 +/- 0.13 pmol/10/sup 6/ cells (n=3). These data suggest that A and ATP stimulate PC secretion by different mechanisms.

• Research Organization: Yale Univ., New Haven, CT
• OSTI ID: 5629813
• Report Number(s): CONF-870644-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 46:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADENOSINE
AMP
ANIMAL CELLS
ANIMALS
ATP
BIOCHEMICAL REACTION KINETICS
CARCINOGENS
CHEMICAL ACTIVATION
ENZYMES
ESTERS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LECITHINS
LIPIDS
MAMMALS
MEMBRANE PROTEINS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHORBOL ESTERS
PHOSPHOLIPIDS
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHOTRANSFERASES
PROTEINS
RATS
REACTION KINETICS
RECEPTORS
RESPIRATORY TRACT CELLS
RESPONSE MODIFYING FACTORS
RIBOSIDES
RODENTS
SECRETION
TRACER TECHNIQUES
TRANSFERASES
TRITIUM COMPOUNDS
VERTEBRATES