Histamine acting on a histamine type 1 (H1) receptor increases beta-glucuronidase release from human lung macrophages.
The effects of histamine on lung macrophages have been studied by both biologic and radioligand experiments. After overnight adherence, lung macrophages spontaneously released beta-glucuronidase (beta-G) at a rate of approximately 7 nmol of hydrolyzed substrate/h/million cells. Histamine at low concentrations (10(-9) to 10(-8) M) resulted in a consistent potentiation of this release. The concentration-effect curve of histamine was bell-shaped, reaching an optimum at 10(-9) M, with concentrations greater than 10(-8) M having no significant effect. At a maximally effective concentration (10(-9) M), histamine evoked a 135 +/- 9.6% (mean +/- SE; n = 8, P less than 0.001) potentiation in the total amount of beta-G released during the first 60 min of incubation. This increase in beta-G release represented both a slight increase in beta-G synthesis as well as an increase in the percentage of beta-G released. When the secreted beta-G is expressed as a percentage of total content, histamine (10(-9) M) evoked a 125 +/- 3.2% (mean +/- SE; n = 27, P less than 0.0005) enhancement. The potentiation of beta-G release by histamine was evident after 45 min of incubation and persisted for up to 6 h. The potentiation of beta-G by histamine was sensitive to inhibition by pyrilamine (10(-7) M).(ABSTRACT TRUNCATED AT 250 WORDS)
Cluzel
M
M
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Liu
M C
MC
Goldman
D W
DW
Undem
B J
BJ
Lichtenstein
L M
LM
D000328:Adult; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D005966:Glucuronidase / Q000378:metabolism*; D006632:Histamine / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D008168:Lung / Q000166:cytology*; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D011738:Pyrilamine / Q000378:metabolism / Q000494:pharmacology; D011969:Receptors, Histamine H1 / Q000187:drug effects / Q000502:physiology*; D012907:Smoking / Q000378:metabolism
D011969:Receptors, Histamine H1; D006632:Histamine; D005966:Glucuronidase; D011738:Pyrilamine