Pulmonary surfactant and its components inhibit secretion of phosphatidylcholine from cultured rat alveolar type II cells

Journal Article · Sun Feb 01 00:00:00 EST 1987 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.84.4.1010· OSTI ID:5722825

Dobbs, L G; Wright, J R; Hawgood, S; Gonzalez, R; Venstrom, K; Nellenbogen, J

Pulmonary surfactant is synthesized and secreted by alveolar type II cells. Radioactive phosphatidylcholine has been used as a marker for surfactant secretion. The authors report findings that suggest that surfactant inhibits secretion of /sup 3/H-labeled phosphatidylcholine by cultured rat type II cells. The lipid components and the surfactant protein group of M/sub r/ 26,000-36,000 (SP 26-36) inhibit secretion to different extents. Surfactant lipids do not completely inhibit release; in concentrations of 100 ..mu..g/ml, lipids inhibit stimulated secretion by 40%. SP 26-36 inhibits release with an EC/sub 50/ of 0.1 ..mu..g/ml. At concentrations of 1.0 ..mu..g/ml, SP 26-36 inhibits basal secretion and reduces to basal levels secretion stimulated by terbutaline, phorbol 12-myristate 13-acetate, and the ionophore A23187. The inhibitory effect of SP 26-36 can be blocked by washing type II cells after adding SP 26-36, by heating the proteins to 100/sup 0/C for 10 min, by adding antiserum specific to SP 26-36, or by incubating cells in the presence of 0.2 mM EGTA. SP 26-36 isolated from canine and human sources also inhibits phosphatidylcholine release from rat type II cells. Neither type I collagen nor serum apolipoprotein A-1 inhibits secretion. These findings are compatible with the hypothesis that surfactant secretion is under feedback regulatory control.

• Research Organization: Univ. of California, San Francisco, CA (United States)
• OSTI ID: 5722825
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 84:4
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
SECRETION
INHIBITION
SURFACTANTS
BIOCHEMISTRY
CELL CULTURES
LUNGS
PHOSPHOLIPIDS
RATS
TRITIUM COMPOUNDS
ANIMALS
BODY
CHEMISTRY
ESTERS
LABELLED COMPOUNDS
LIPIDS
MAMMALS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANS
RESPIRATORY SYSTEM
RODENTS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques