Background : The neurohypophysis of toad Sclerophrys regularis contains at least three types of neuropeptides : vasotocin, hydrin-2 and seritocin. Vasotocin (AVT) and hydrin 2 are widely studied, but the effects of seritocin on the organs of osmoregulation such as skin, kidneys and bladder are not sufficiently documented. The aim of this work was to determine the effect of seritocin on the pelvic skin of the toad Sclerophrys regularis, the total water intake (TWI) and water balance (WB).
Materials and Methods : We used the Ussing chamber on which the pelvic skin pre-incubated with neuropeptides was mounted. A graduated pipette was used to monitor the water level on the serosal side of the Ussing chamber. Then, neuropeptides was administered subcutaneously to observe their effects on TWI and WB.
Results : Our results indicate that AVT and hydrin 2 increase the water permeability of the skin. They stimulate TWI and WB. Seritocin does not promote water permeability of the pelvic skin of the toad Sclerophrys regularis. It does not stimulate TWI or WB in particular. Seritocin appears to be an antagonistic hormone to AVT and hydrin-2.
Conclusion : These results suggest that seritocin, contrary to hydrin 2 and AVT, does not stimulate water uptake in the pelvic skin nor its reabsorption in the bladder and kidneys.

Sclerophrys regularis, seritocin, Hydroosmotic activity, water balance