The testosterone metabolite and neurosteroid 3alpha-androstanediol may mediate the effects of testosterone on conditioned place preference.

Abstract

Testosterone (T) and pregnane neurosteroids can enhance conditioned place preference (CPP). The present experiment examined CPP produced by T and its androgenic metabolite dihydrotestosterone (DHT) and 3alpha-Androstanediol (3alpha-diol; an androstane neurosteroid). Administration of 3alpha-diol (>DHT>T) to intact male Long-Evans rats, 1.0 mg daily for six days, 30 min prior to exposure to the non-preferred side of the CPP chamber significantly increased preference for the non-preferred side of the chamber compared to that seen in home cage controls. Levels of circulating 3alpha-diol were increased significantly in 3alpha-diol>DHT>T-administered rats, compared to rats that had vehicle administered or androgen-administration discontinued. Androgen administration decreased seminal vesicle weight and intrahypothalamic androgen receptor (AR) binding compared to that seen in rats that had vehicle administered or androgen-administration discontinued. Testosterone, DHT, and 3alpha-diol decreased GABA-stimulated chloride influx in cortical synaptoneurosomes, and muscimol binding in the hippocampus compared to that seen in rats with vehicle administered or that had androgen-administration discontinued. These data indicate that administration of 3alpha-diol is more effective at enhancing CPP and increasing circulating 3alpha-diol levels than is DHT or T administration, and that all of the androgen regimens employed decreased peripheral and hypothalamic androgen receptor binding and cortical and hippocampal GABA(A) receptor function. Hence, whether the effects of 3 alpha-diol on CPP are mediated by differential actions at ARs or GABA(A) receptors in particular brain regions needs to be determined.