ACTIVITY OF PEPTIDASE-1, A SEX-LINKED ENZYME, DURING LARVAL DEVELOPMENT AT NORMAL OR SEX REVERSAL REARING TEMPERATURE AND ACCORDING TO TISSUES IN ADULTS OF PLEURODELES WALTL (URODELE AMPHIBIAN)

Peptidase-l is a sex linked marker routinely used in laboratories to d etermine the sexual genotype of Pleurodeles waltl individuals. This ur odele amphibia displays a ZZ/ZW sex determination system at room tempe rature bur can be sex-reversed by heat treatment. The physiological ro le of peptidase-l in cells or organs is unknown. The peptidase-l codom inant genes are located in the differential segments of the sex chromo somes Z and W. Because of this location, peptidase-l could play a role during the larval development in gonadal sex differentiation. On the one hand, results indicate no peptidase-1 differential expressions bet ween control larvae and larvae treated for sex reversal by the rearing temperature. On thr other hand, in the case of adult animals, signifi cant specific activity differences in gonads, in muscle, stomach, hear t and kidney between males and females were observed. The ubiquitous d etection of peptidase-1 indicates that this sex-linked enzyme does nor display a key role in gonadal sex determination.