Experimental hypercalcemia induces hypocalcin release and inhibits branchial Ca2+ influx in freshwater trout.
Intravascular CaCl2 infusion in freshwater rainbow trout (Salmo gairdneri) causes a significant degranulation of the corpuscles of Stannius (CS). Concurrently, there is a specific and acute inhibition of whole body Ca2+ influx; Ca2+ efflux is not effected. The material released from the CS after CaCl2 injection consists primarily of a 28-kDa product which we identified as hypocalcin. Electron microscope observations of the CS reveal that type 1 and type 2 cells are degranulated to a similar extent. We conclude that hypocalcin is directly involved in hypocalcemic control in freshwater fish via inhibition of branchial Ca2+ influx, thereby promoting a net loss of Ca2+ across the gill.
Lafeber
F P
FP
Department of Biology, University of Ottawa, Ontario, Canada.
Perry
S F
SF
D000818:Animals; D002118:Calcium / Q000097:blood / Q000378:metabolism*; D002122:Calcium Chloride / Q000494:pharmacology*; D005880:Gills / Q000378:metabolism*; D006934:Hypercalcemia / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology*; D012487:Salmonidae / Q000502:physiology*; D012965:Sodium Chloride / Q000494:pharmacology; D014337:Trout / Q000502:physiology*
D012965:Sodium Chloride; D002122:Calcium Chloride; D002118:Calcium