Relationship between serum testosterone and nocturia in men without benign prostate enlargement.

Recent studies have focused on the relationship between nocturia and serum testosterone because testosterone is thought to be an important factor of prostate growth. However, it remains unclear whether altered serum concentrations of testosterone is associated with an increased risk of nocturia because patients who were taking diuretics or who had a large prostate, which may precipitate nocturia, were not excluded from most previous studies. We analyzed the clinical records of 596 non-benign prostatic enlargement (BPE) male patients to explore the relationship between serum total testosterone and nocturia. All patients were evaluated using a serum prostate-specific antigen (PSA) assay, measurement of serum total testosterone, transrectal ultrasonography, uroflowmetry, and a compilation of the International Prostate Symptom Score (IPSS) and International Index of Erectile Function (IIEF) questionnaires. Nocturia was defined as ≥2 nocturnal voiding episodes. The number of nocturia episodes was assessed using IPSS question 7. To evaluate the effect of serum testosterone on nocturia, multivariate regression analysis was performed including the covariates of age, IPSS, IIEF score, body mass index, PSA, prostate volume, and maximal urine flow rate. Based on multivariate linear analysis, serum testosterone level was not significantly associated with the severity of nocturia. However, with regard to the relationship between prevalence of nocturia and serum testosterone, prevalence of nocturia was significantly positively associated with age (OR = 1.048, p = 0.005), total IPSS (OR = 1.217, p < 0.001), and testosterone level (OR = 1.150, p = 0.041). Therefore, in men without an enlarged prostate, testosterone may play an opposing role in the etiology of nocturia.

The relaxation effect and mechanism of action of higenamine in the rat corpus cavernosum.

Higenamine mediates cardiotonic, vascular relaxation and bronchodilator effects. The relaxation effects and the mechanism of action of higenamine on the rat corpus cavernosum (CC) were assessed to investigate the effect of higenamine on penile erection. Strips of CC and aorta were used in organ baths for isometric tension studies. Tension was measured with isometric force transducers, and muscle relaxation was expressed as the percent decrease in precontraction induced by phenylephrine (PE). The relaxation reactions were investigated in an endothelial-denuded group and groups pretreated with N(G)-nitro-L-arginine methyl ester (NO synthesis inhibitor), propranolol (ß-receptor blocker), indomethacin (COX inhibitor), glibenclamide (K(+)(ATP) channel inhibitor), 4-aminopyridine (membrane potential-dependent potassium channel inhibitor) and methylene blue (guanylyl cyclase inhibitor) for 30 min. Intracavernous pressure (ICP) was assessed in rats after the intravenous administration of higenamine, and changes in guanosine 3',5'-cyclic monophosphate and adenosine 3',5'-cyclic monophosphate (cAMP) concentrations were measured on the basis of the higenamine concentration. Also, the combined reaction of higenamine and the phosphodiesterase type-5 (PDE-5) inhibitors was assessed. Higenamine induced relaxation of the CC and the aortic strips precontracted with PE in a dose-dependent manner. The CC was significantly more relaxed than the aortic rings in response to the same higenamine concentration (P<0.05). The CC relaxation reaction was suppressed by the ß-receptor blocker propranolol. The cAMP concentration increased gradually with increased higenamine concentration (P<0.05). The ICP also increased with increased higenamine concentration in vivo (P<0.05). In the group pretreated with 10(-7) M higenamine, the relaxation reaction of CC induced by the PDE-5 inhibitor increased significantly, compared with CC exposed to the PDE-5 inhibitor but not pretreated with higenamine (P<0.05). In conclusion, higenamine induced relaxation of the rat CC in a dose-dependent manner. The effect may be mediated through ß-adrenoceptors. The results suggest that higenamine may be valuable as a new lead compound for treating erectile dysfunction.