title: Novel digitalis-like factor, marinobufotoxin, isolated from cultured Y-1 cells, and its hypertensive effect in rats.
abstract: Marinobufagenin and telecinobufagin have been identified as digitalis-like factors in mammals. In toads, marinobufagenin-related compounds, such as marinobufotoxin (MBT), have been isolated in some tissues but not in mammals, and its biological action has not been elucidated. Herein, we aimed to explore the possible production and/or secretion of MBT and the biological action in rats. First, the MBT in culture supernatant of the adrenocortical-originated cell line Y-1 was analyzed by high-performance liquid chromatography and sensitive ELISA for marinobufagenin-like immunoreactivity. Moreover, the structural information was obtained by mass spectrometry. To determine the biological action, MBT (9.6 and 0.96 microg/kg per day) was intraperitoneally infused via an osmotic minipump for 1 week. Blood pressure and renal excretion of marinobufagenin-like immunoreactivity were measured. Marinobufagenin-like immunoreactivity was found in Y-1 cell culture media, and the concentration increased until 24 hours. The structural analysis suggested that marinobufagenin-like immunoreactivities were marinobufagenin and MBT, and tandem mass spectrum analysis revealed them with the specific daughter ions. The highest sensitive ELISA-positive peak of marinobufagenin-like immunoreactivity in the media was MBT. Continuous administration of MBT in rats for 1 week significantly increased systolic blood pressure and renal excretion of marinobufagenin-like immunoreactivity compared with control rats (135+/-3.0 versus 126+/-2.0 mm Hg and 1.41+/-0.286 versus 0.34+/-0.064 ng/day, respectively). These data suggest that MBT, arginine-suberoyl ester of marinobufagenin, can be a novel digitalis-like factor with hypertensive action and is secreted from the adrenocortical cells.
authors.affiliation: Department of Clinical Sciences and Laboratory Medicine, Kansai Medical University, Fumizonocho, Moriguchi, Osaka 570-8507, Japan.
authors.forename: Masamichi
authors.initials: M
authors.lastname: Yoshika
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Komiyama
authors.forename: Motomi
authors.initials: M
authors.lastname: Konishi
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Akizawa
authors.forename: Takahisa
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Mutsuhiro
authors.initials: M
authors.lastname: Date
authors.forename: Shinzo
authors.initials: S
authors.lastname: Kobatake
authors.forename: Midori
authors.initials: M
authors.lastname: Masuda
authors.forename: Hiroya
authors.initials: H
authors.lastname: Masaki
authors.forename: Hakuo
authors.initials: H
authors.lastname: Takahashi
mesh_terms: D000302:Adrenal Cortex / Q000737:chemistry* / Q000166:cytology; D000818:Animals; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D001794:Blood Pressure / Q000187:drug effects; D002018:Bufanolides / Q000276:immunology / Q000652:urine; D002297:Cardanolides / Q000008:administration & dosage / Q000302:isolation & purification* / Q000494:pharmacology; D002298:Cardenolides / Q000008:administration & dosage / Q000302:isolation & purification* / Q000494:pharmacology; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D004334:Drug Administration Schedule; D004797:Enzyme-Linked Immunosorbent Assay; D006973:Hypertension / Q000139:chemically induced*; D007274:Injections, Intraperitoneal; D008297:Male; D013058:Mass Spectrometry; D051381:Rats; D017208:Rats, Wistar; D012503:Saponins / Q000008:administration & dosage / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D002018:Bufanolides; D002297:Cardanolides; D002298:Cardenolides; D012503:Saponins; C034504:digoxin-like factors; C516149:marinobufotoxin; C093896:marinobufagenin