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RESEARCH PRODUCT

Some effects of salmon calcitonin on calcium metabolism in the crustaceanOrchestia during the molt cycle

subject

description

In the terrestrial amphipod Orchestia cavimana, investigations of the variations of the total hemolymphatic calcium during the normal molt cycle revealed that a calcium balance is maintained in intermolt, as observed in numerous crustaceans. During premolt, hypercalcemia occurs, related to the marked calcium reabsorption from the old cuticle, which may promote the storage of a part of this calcium within the midgut posterior caeca. The calcium levels fall after exuviation to late postmolt to the low basal levels of intermolt; this may reflect the imbalance between the rates of calcification of the newly secreted cuticle and uptake of calcium within the posterior caeca. Administration of salmon calcitonin lowers calcium levels in intermolt and early premolt, when endogenous calcitonin-like activity and ecdysteroid titers are low, but has no effect in late premolt when endogenous calcitonin-like activity is important.