Effects of chronic prenatal, neonatal and adult exposure to barbiturates on mitochondrial benzodiazepine receptors in mouse testis

In the present study we investigated the effect of chronic exposure to phenobarbital, administered to mice during the prenatal or neonatal period, as well as to adult mice, on mitochondrial benzodiazepine receptors in the testis. Three modes of treatment were investigated: (1) offspring of pregnant mice receiving food containing 3 g/kg phenobarbital until gestational day 18 were killed at 22 or 50 days of age and assayed for receptor binding (prenatal group); (2) offspring of untreated mice were injected subcutaneously once daily with 50 mg/kg phenobarbital on days 2-21 of age and killed at 22 or 50 days of age (neonatal group); (3) adult mice were injected subcutaneously once daily for 3 weeks with 50 or 100 mg/kg phenobarbital (adult group). Prenatal or neonatal exposure to phenobarbital did not alter the testicular weight in all groups (except for the neonatally exposed group killed at 22 days of age), or the mitochondrial benzodiazepine receptor binding characteristics. However, the maximal number of these receptors in the testes of mice in the adult group receiving 100 mg/kg phenobarbital was significantly increased (42%, P < 0.05), compared to controls. The administration of 50 mg/kg phenobarbital to the adult group also induced an increase (27%, non-significant) in testicular mitochondrial benzodiazepine receptors. Phenobarbital administration did not affect the receptor affinity values or the weight of the testis. It is unclear whether these receptor alterations due to chronic phenobarbital exposure of adult mice reflect functional changes in the testis.