Endocrine Abstracts

Seminal vesicles play important roles in male infertility due to their secretions and contractile properties. Beside their sympathetic and parasympathetic nerve supply, seminal vesicles are also innervated by purinergic stimuli. Additionally, prolactin affects the gonadal, seminal vesicle, prostate functions and contributes to seminal plasma and sexual function. Medical treatment of hyperprolactinemia usually involves dopamine agonists. In the present study, effects of treated and untreated hyperprolactinemia on the contractility of isolated seminal vesicle were investigated. A total of 24 Wistar rats, weighing 285 g, were randomly divided into three groups: control group, prolactin received group (14 mg/kg) and prolactin (14 mg/kg) + bromocriptine (0.7 mg/kg) received group. Seminal vesicles of all rats were isolated following decapitation and 0.5x0.2 cm strips were suspended in a jacketed organ bath containing Krebs solution at 37degC, continuously bubbled with 95% O2 and 5% CO2. Isometric contractions were evoked either by acetylcholine (ACh, 10 micromolar) or KCl (100mM). The amplitude of KCl induced contractions were 1586.66 ± 121.40 mg, 2234.85 ± 164.44 mg (p<0.5) and 1208.60 ± 164.44 in the control, prolactin and prolactin + bromocriptine groups, respectively. The amplitude of ACh induced contractions were 1758.83±232.72 mg, 2525.55 ± 194.84 mg and 1373.80 ± 130.68 mg control, prolactin group and prolactin + bromocriptin groups, respectively. Mean amplitude of ACh and KCl-induced contractions were significantly higher in prolactin group than the other groups (p<0.05). Results from this study indicate that hyperprolactinemia increases contractility and tonus of smooth muscle of seminal vesicles. Since alterations in smooth muscle tone of seminal vesicles and other genitourinary tract organs may further contribute to infertility, patients with hyperprolactinemia should be carefully evaluated for their smooth muscle tonus of genito-urinary organs.