RESUMEN
<p><b>OBJECTIVE</b>To study the changes in the mRNA expression of insulin-like factor 3 (INSL-3) in the testis of mouse models of flutamide-induced cryptorchidism.</p><p><b>METHODS</b>We randomized pregnant BALB/c mice to groups A (control) , B, C, D and E to receive continuous gavage of flutamide at 0, 150, 300, 500 and 700 mg/kg body weight, respectively, from gestation day 12 to 21. We detected the expression of INSL-3 mRNA in the testis of the neonates by real-time PCR at 4 and 8 postnatal weeks.</p><p><b>RESULTS</b>No cryptorchidism was found in group A; unilateral cryptorchidism was seen in groups B (10.0%) and C (25.0%); and bilateral cryptorchidism was observed in groups D (21.1%) and E (40.0%). The expression of INSL-3 mRNA was reduced with the increased dose of flutamide, not significantly changed in groups B and C (P > 0.05) but remarkably decreased in D and E as compared with A (P < 0.05).</p><p><b>CONCLUSION</b>Administration of flutamide to pregnant mice can induce unilateral cryptorchidism at 150 and 300 mg/kg and bilateral cryptorchidism at 500 and 700 mg/kg in their male offspring, which may be related with its reducing effect on the expression of INSL-3 in the testis of the mice.</p>