Acute changes in gill Na+-K+-ATPase and creatine kinase in response to salinity changes in the euryhaline teleost, tilapia (Oreochromis mossambicus).
Some freshwater (FW) teleosts are capable of acclimating to seawater (SW) when challenged; however, the related energetic and physiological consequences are still unclear. This study was conducted to examine the changes in expression of gill Na(+)-K(+)-ATPase and creatine kinase (CK) in tilapia (Oreochromis mossambicus) as the acute responses to transfer from FW to SW. After 24 h in 25 ppt SW, gill Na(+)-K(+)-ATPase activities were higher than those of fish in FW. Fish in 35 ppt SW did not increase gill Na(+)-K(+)-ATPase activities until 1.5 h after transfer, and then the activities were not significantly different from those of fish in 25 ppt SW. Compared to FW, the gill CK activities in 35 ppt SW declined within 1.5 h and afterward dramatically elevated at 2 h, as in 25 ppt SW, but the levels in 35 ppt SW were lower than those in 25 ppt SW. The Western blot of muscle-type CK (MM form) was in high association with the salinity change, showing a pattern of changes similar to that in CK activity; however, levels in 35 ppt SW were higher than those in 25 ppt SW. The activity of Na(+)-K(+)-ATPase highly correlated with that of CK in fish gill after transfer from FW to SW, suggesting that phosphocreatine acts as an energy source to meet the osmoregulatory demand during acute transfer.
Weng
Ching-Feng
CF
Institute of Biotechnology, National Dong Hwa University, Hualien, Taiwan 947, Republic of China.
Chiang
Chia-Chang
CC
Gong
Hong-Yi
HY
Chen
Mark Hung-Chih
MH
Lin
Cliff Ji-Fan
CJ
Huang
Wei-Tung
WT
Cheng
Ching-Yi
CY
Hwang
Pung-Pung
PP
Wu
Jen-Leih
JL
D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D003402:Creatine Kinase / Q000502:physiology*; D005618:Fresh Water; D005880:Gills / Q000201:enzymology*; D012623:Seawater / Q000009:adverse effects; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D017210:Tilapia / Q000502:physiology*
D003402:Creatine Kinase; D000254:Sodium-Potassium-Exchanging ATPase