CHANGES IN ECDYSTEROID LEVELS DURING REGENERATION OF A LIMB IN PILUMNUS-HIRTELLUS

Measurements of ecdysteroid levels were made in hemolymph, epidermis a nd regenerating limb of Pilumnus hirtellus crabs after autotomy of one pereiopod performed during stage C4 of the molting cycle. Comparison of the evolution of ecdysteroid profiles indicated that during the pre molt period the epidermis and the regenerating limb behave like authen tic target tissues, whereas during the transition period from intermol t to premolt, a hormone increase observed in the regenerate could be a result of autocrine activity. This increase is correlated with intens e proliferative activity of the cells of the limb bud which enter thei r basal growth period.