Identification of hypocalcin (teleocalcin) isolated from trout Stannius corpuscles.
نویسندگان
چکیده
We have isolated and purified a glycoprotein from the corpuscles of Stannius (CS) of trout, which we consider hypocalcin (also called teleocalcin), the major hypocalcemic hormone of fish. This product is present in relatively large amounts in the CS of several species (i.e., European eel, tilapia, goldfish, and carp). Hypocalcin is typically released from the CS in response to an experimentally induced increase of the blood calcium concentration. Ultrastructural observations show that after this treatment the type 1 cells, reportedly the hypocalcin-producing cell type of the CS, are almost completely degranulated. The isolated glycoprotein has an apparent molecular weight of 54 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This molecule appears susceptible to breakdown and is recovered upon concanavalin-A affinity chromatography as a 41 kDa product. Reducing agents such as mercaptoethanol or dithiothreitol employed, e.g., during standard electrophoretic techniques or during amino acid sequence analysis, allow only the recovery of 28 or 18 kDa products. Evidence is given that the 54 and 41 kDa products are dimer molecules, with the 28 and 18 kDa products as their respective monomeric constituents. The sequence of the first 33 N-terminal amino acids of these products and the composition of the sugar component are presented.
منابع مشابه
Hypocalcin from Stannius corpuscles inhibits gill calcium uptake in trout.
Bidirectional whole body flux and branchial Ca2+ influx were measured in freshwater rainbow trout. Intra-arterial injections of homogenates of Stannius corpuscles (CS) as well as of a 54-kDa isolated product (hypocalcin) exerted an inhibitory effect on whole body Ca2+ influx, but did not effect Ca2+ efflux. Hypocalcin was more effective in reducing Ca2+ influx in trout acclimated to low-calcium...
متن کاملRainbow trout hypocalcin stimulates bone resorption in embryonic mouse calvaria in vitro in a PTH-like fashion.
Hypocalcin, the major hormone with hypocalcaemic action in fish, was isolated from trout corpuscles of Stannius (SCs). The bioactivity of hypocalcin was assessed in a parathyroid hormone (PTH) bioassay involving bone resorption in embryonic mouse calvaria. Calcium and phosphate release and lactate production were stimulated in a dose-dependent manner by hypocalcin. On a molar basis about equal ...
متن کاملIonic and total calcium levels in the blood of the European eel (Anguilla anguilla): effects of stanniectomy and hypocalcin replacement therapy.
Removal of the corpuscles of Stannius (STX) in the freshwater European eel causes a marked increase in the concentrations of blood ionic calcium and protein-bound calcium. The hypercalcaemia peaks 20 days after STX and lasts at least another 20 days. In stanniectomized eels hypocalcin decreased both blood ionic and total calcium concentrations. The reduction of plasma total calcium concentratio...
متن کاملEffects of stanniocalcin 1 on calcium uptake in zebrafish (Danio rerio) embryo.
Stanniocalcin (STC) formerly called hypocalcin or teleocalcin, is a 50-kDa disulfide-linked homodimeric glycoprotein that was originally identified in fish and secreted from the corpuscles of Stannius (CS). One of the main functions of STC-1 is Ca(2+) uptake inhibition; however, the mechanisms remain unknown. In the present study, we provide molecular evidence to elucidate how zebrafish STC-1 r...
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ورودعنوان ژورنال:
- General and comparative endocrinology
دوره 69 1 شماره
صفحات -
تاریخ انتشار 1988