Stimulation of calcium efflux from the hagfish, Eptatretus cirrhatus, gill pouch by an extract of corpuscles of Stannius from an eel (Anguilla dieffenbachii): teleostei.
A factor present in the homogenate of the corpuscles of Stannius from a teleost, the longfin eel Anguilla dieffenbachii, showed calcitropic effects in an agnathan, the hagfish Eptatretus cirrhatus. This factor greatly increased calcium efflux from an isolated perfused gill pouch preparation and had no effect on calcium influx. Hagfish regulated plasma total calcium at a concentration which was about 50% of that of the ambient seawater. Intact hagfish had rates of calcium influx and efflux which were similar to those recorded in teleosts. Hagfish are thus similar to teleosts to the extent that they can and do maintain a plasma calcium concentration which is quite different from that of the ambient medium. They also resemble teleosts in that transepithelial calcium fluxes across the hagfish gill pouches respond to extracts of Stannius corpuscles. Hagfish, however, are quite unlike teleosts in that the Stannius corpuscle extract stimulates calcium efflux rather than inhibiting calcium influx.
Forster
M E
ME
Department of Zoology, University of Canterbury, Christchurch, New Zealand.
Fenwick
J C
JC
D000811:Anguilla; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002132:Calcium Radioisotopes; D004702:Endocrine Glands / Q000502:physiology*; D005880:Gills / Q000098:blood supply / Q000378:metabolism*; D006196:Hagfishes / Q000378:metabolism*; D007545:Isoproterenol / Q000494:pharmacology; D007700:Kinetics; D014020:Tissue Extracts / Q000494:pharmacology; D014655:Vascular Resistance / Q000187:drug effects
D002132:Calcium Radioisotopes; D014020:Tissue Extracts; D007545:Isoproterenol; D002118:Calcium