Summary:Neither resting nor stimulated isolated human polymorphonuclear leukocytes did bind or ingest preformed complexes of a r prpteinase Inhibitor and unlabeled/ 125 I-labeled human leukocyte elastase. In contrast, granulocytes bound unlabeled/ 125 I-labeled elastase and the extent of binding was reduced in the presence of respirätory burst stimulators, such äs 4ß-phorbol 12ß-myristate 13a-acetate, E. coli endotoxin, and N^formyl-jL-methionyl-L-leucyl-L-phenylalanine. In association/dissociation and competition Inhibition experiments it was demonstrated that granulöcyte^-elastase binding was specific and saturable. From Scatchard and non-linear regression analysis there was evidence of a two-class receptor model with independent binding sites. Calculated by the non-linear regression method assuming a two-class receptor model the characteristics of the high affinity/low capacity binding site were K! = 216 ± 129 · l O 6 l · mol" 1 (x ± s; n = 3) and Rj = 1.38 ± 0.95 nmol · 1~* corresponding to 0.083 · 10 6 receptors per cell, whereäs the low affinity/ high capacity binding site had the characteristics K 2 = 0.50 ± 0.09 -10 6 l-mol^1 and R 2 = 237 ± 103 nmol · l" 1 corresponding to 14.3 + 6.2 -10 6 receptors per cell. ]Elastase-Bindung in Gegenwart der respiratory burst-Stimulantien 4ß-Phorbol-12ß-myristat-13a-acetat, E. co/rVEndotoxin und Formyl-methionyl-leucyl-phenylalanin erniedrigt ist. Aus Assoziations-/Dissoziationsund Kompetitions-Inhibitions-Experimenten geht hervor, daß die Granulocyten-Elastase-Bindung spezifisch und sättigbar ist. Scatchard-und nichtlineare Regressions-Analyse deuten auf ein zweiklassiges Modell unabhängiger Rezeptoren hin. Aus der nichtlinearen Regressionsanalyse ergeben sich unter Annahme eines zweiklassigen Rezeptormodelis die Bindungskonstanten Kj = 216 ± 129 · l O 6 1 · mol' 1 (x ± s; n = 3) und Rj = 1,38 ± 0,95 nmol · l" 1 entsprechend 0,083 · l O 6 Rezeptoren pro Zelle für die hochaffine/niedrigkapazitive Bindungsstelle, während die niedrigaffine/hochkapazitive Bindungsstelle die Konstanten K 2 = 0,50 ± 0,09 • 10 6 l -mol-1 Und R 2 « 237 ± 103 nmol · l^1 entsprechend 14,3 ± 6,2 · 10 6 Rezeptoren pro Granulocyt besitzt. Untersuchungen zur Elastase* und a,i~Proteinaseinhibitor-Elastase-Aufnahme polymorphkerniger Leukocyten und Nachweis eines Elastaserezeptor^Systems

By using a modified Scatchard analysis, statistically significant differences were observed between the receptor affinities of the groups A aiid D, B and D, A and C.The receptor affinities and concentrations were not significantly different between the follicular and the luteal phases. From the data, no inverse correlation between the plasma insulin concentration and receptor binding was seen, i.e. the phenömenon of downiegulation pf insulin receptor concentration with hyperinsulinaemia seemed not to apply to erythrocytes.The present results suggest that insulin binding to erythrocytes is mpdulated preferably or even exclusively by an alteration of receptor affinity and that short-term chariges in insulin binding to erythroeytes are not caused by an alterätion of receptor concentration. Vergleich der Bindung von Insulin an Erythrocyten während und nach Schwangerschaft und in der Proliferationsund der Sekretionsphase des Menstruations-Cyclus

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