Purification and properties of endogenous ouabain-like substances from hemofiltrate and adrenal glands.
Chick embryo heart cells in culture were found to contain two cell types differing in their [Ca2+]i. Elevation of [Ca2+]i in cells with 99.4 +/- 7.1 nM [Ca2+]i was induced half-maximally at 2 x 10(-9) M ouabain and of cells with 27.9 +/- 4.4 nM [Ca2+]i at 4 x 10(-8) M ouabain. The localization of a sodium pump with differing sensitivity for ouabain in different cell types of the heart raised the question of the existence of endogenously formed ouabain. From 6,000 I hemofiltrate of uremic patients, a substance of 582 Da cross-reacting with ouabain antibodies was purified 42,000-fold. The substance was slightly more hydrophobic on a C-18 reversed-phase high-performance liquid chromatography (HPLC) than ouabain was. It inhibited 86Rb+ uptake into red blood cells and raised like ouabain [Ca2+]i in both types of chick heart cells. From pig adrenal glands, a substance inhibiting 86Rb+ uptake into erythrocytes was purified by affinity chromatography on a column containing antibodies against ouabain. A major part of the eluted substances chromatographed on a C-18-HPLC column as ouabain did, but a minor part was somewhat more hydrophobic. It is presumed that more than a single endogenous ouabain-like factor exists in mammals.
Schoner
W
W
Institut für Biochemie und Endokrinologie, Justus-Liebig-Universität Giessen, Germany.
Heidrich-Lorsbach
E
E
Kirch
U
U
Ahlemeyer
B
B
Sich
B
B
D000311:Adrenal Glands / Q000737:chemistry*; D000368:Aged; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D006440:Hemofiltration; D006801:Humans; D008297:Male; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism; D010042:Ouabain / Q000032:analysis* / Q000097:blood / Q000302:isolation & purification / Q000494:pharmacology; D012413:Rubidium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors*; D013552:Swine; D014511:Uremia / Q000378:metabolism*
D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase; D012413:Rubidium; D002118:Calcium