3 Intraperitoneal administration of CB compounds (3 ± 50 mg kg 71 ) induced a dose-dependent increase in the concentrations of neuroactive steroids in plasma and brain. The brain concentrations of pregnenolone, progesterone, allopregnanolone and allotetrahydrodeoxycorticosterone (THDOC) showed maximal increases in 96+3, 126+14, 110+12 and 70+13% above control, respectively, 30 to 60 min after injection of CB 34 (25 mg kg 71 ). CB 34 also increased the brain concentrations of neuroactive steroids in adrenalectomized-orchiectomized rats, although to a lesser extent than in sham-operated animals, suggesting that CB compounds stimulate brain steroidogenesis independently of their e ects on peripheral tissues. 4 The increase in brain and plasma neurosteroid content induced by CB 34 was associated with a marked anticon¯ict e ect in the Vogel test. Our results indicate that the three CB compounds tested are speci®c and potent agonists at peripheral benzodiazepine receptors, and that they stimulate steroidogenesis in both the brain and periphery.