[Peri- and postnatal study on halopredone acetate in rats].

A peri- and postnatal study of halopredone acetate (THS-201), a synthetic corticosteroid, was carried out using Jcl: Wistar rats. Pregnant rats were treated subcutaneously in doses of 0.05, 0.4, 3.2 and 25.6 mg/kg/day, from day 17 of gestation to day 21 after delivery. All pregnant rats were allowed to litter naturally, and the postnatal development of offsprings was observed. The results obtained from the present study were as follows. No influences of THS-201 administration were observed on gestation, delivery and lactation of dams. THS-201 administration did not have any influences on viability and development, various functions such as reflex response, learning and reproductive performance of F1 generation, and further on development of F2 generation. Therefore, it was concluded that the non-effect dose of THS-201 for the reproduction of dams and development of F1 generation was 25.6 mg/kg/day.