AGE-RELATED RESPONSES OF HEPATIC ATPASES TO STARVATION AND COLD STRESS IN MALE GARDEN LIZARDS

Hepatic Na+-K+-ATPase and Mg2+-ATPase activities of male green lizards declined during the maturation phase (juvenile to I-year-old) and sta bilized thereafter. On the other hand, the Ca2+-ATPase activity of the liver declined during the later half of the life span (1-year-old to 2-4-year-old), Starvation stress induced a decline in hepatic Na+-K+-A TPase and Mg2+-ATPase activities of juvenile lizards and caused an inc rease in 1-year-old and 2-4-year-old counterparts. The Ca2+-ATPase act ivity declined only in starved 1-year-old lizards, Following cold stre ss, the hepatic Na+-K+-ATPase activity of juvenile lizards showed a hi gher degree of decline than 2-4-year-old counterparts. The Mg2+-ATPase activity declined in cold-stressed juvenile lizards, but the paramete r was elevated in similarly treated 1-year-old lizards, On the other h and, the increase in Ca2+-ATPase activity in response to cold stress w as confined only to 2-4-year-old lizards.