Abstract

The contractile and pressor responses of isolated, superfused seminal vesicles to angiotensin (10-20 µg), barium chloride (1-4 mg), tyramine (100-200 µg), epinephrine (E; 10-20 µg) and norepinephrine (NE; 10-20 µg) were reduced or absent in organs obtained from guinea pigs treated with testosterone (10 mg/kg/day for eight days i.p.) as compared to peanut oil (1.0 ml/kg/day for eight days i.p.) controls. NE and E content of the seminal vesicles was determined by fluorometric assay with the trihydroxyindole method; adrenergic innervation was studied with fluorescence histochemistry and electron microscopy. After treatment with testosterone the content of E was variable but the NE content decreased from 10.7 ± 1.2 µg/g to 3.2 ± 1.8 µg/g. The number of fluorescent adrenergic nerves and the proportion of granular synaptic vesicles, as examined by fluorescence and electron microscopy, respectively, were decreased after testosterone treatment. These results demonstrate that testosterone in high concentrations may reduce adrenergic function by decreasing the transmitter content of the adrenergic nerves of the seminal vesicle. The reduction in the responses to NE, E and BaCl₂ after testosterone administration suggests that this steroid may depress the sensitivity of the seminal vesicle adrenergic receptors and/or the smooth muscle cell.