title: Age-related decline in ligand-induced actin polymerization in human leukocytes and platelets.
abstract: The change in monomeric actin was measured in human polymorphonuclear leukocytes (PMN) and platelets, using the DNase I inhibition assay, after stimulation with various agents. PMN were stimulated with the chemotactic peptide n-formyl-methionyl-leucyl-phenylalanine (FMLP) in 199 donors, the tumor promoter phorbol myristate acetate in 112 donors, and the hormones tri-iodothyronine and phenylephrine, in 118 donors. The donors ranged in age from 20 to 89 years. A decrease in ligand-induced actin polymerization was detected in PMN obtained from the older population, on stimulation with FMLP (p = .014) and PMA (p = .0038). In platelets stimulated with thrombin (163 donors) a significant decrease in actin polymerization also was noted in the older group (p = .017). In addition, in platelets actin polymerization was less in women compared with men (p = .042). Because actin polymerization is an event that might have an important role in cellular activation, the age-related decline in the physiological functions might be related to a decrease in ligand-induced actin polymerization.
mesh_terms: D000199:Actins / Q000097:blood*; D000328:Adult; D000368:Aged; D000375:Aging; D001792:Blood Platelets / Q000187:drug effects*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008024:Ligands; D008297:Male; D008875:Middle Aged; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects*; D010656:Phenylephrine / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014284:Triiodothyronine / Q000494:pharmacology
chemical_list: D000199:Actins; D008024:Ligands; D014284:Triiodothyronine; D010656:Phenylephrine; D009240:N-Formylmethionine Leucyl-Phenylalanine; D013755:Tetradecanoylphorbol Acetate