Calcitonin-like substance in plasma of the hagfish, Eptatretus burgeri (Cyclostomata).

概要

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Cyclostomes have been regarded as having no ultimobranchial gland. However, cells producing immunoreactive calcitonin (CT) were recently found in cyclostome brains. In the present study, we examined using biochemical and biological methods whether there is a CT-like substance in the plasma of the hagfish, Eptatretus burgeri. Hagfish plasma was first subjected to reverse-phase high-performance liquid chromatography (RP-HPLC) and then separated into twenty fractions. The presence of immunoreactive CT in each fraction was then investigated by Western blotting with salmon CT antiserum. Two fractions (36-39% CH3CN; 39-42% CH3CN) showed positive immunoreactivity. Hypocalcemic and hypophosphatemic activities were detected by a rat bioassay only in the former fraction (36-39% CH3CN). The molecular weight (MW) of the CT-like substance in this fraction was 3.5 kDa, which is equal to that of genuine CT. Furthermore, when hagfish plasma was examined by enzyme-linked immunosorbent assay using anti-salmon CT, the dilution curve of the plasma paralleled the standard curve of salmon CT. The CT-like substance detected here was present at a high concentration (14 ng/ml) in the plasma. From the results of the present study, the CT-like substance present in hagfish plasma appears to be very similar to salmon CT.
社団法人日本動物学会の論文
1995-10-15