Leptin Enhances Nitric Oxide-Dependent Relaxation of the Clitoral Corpus Cavernosum

PURPOSE: The effects of leptin on female sexual behaviors are controversial, and studies on this topic are limited. The objectives of this study were to evaluate the direct effects of leptin on clitoral vasoreactivity in vitro and to determine the mechanism of action. MATERIALS AND METHODS: Isometric tension studies were conducted to determine the effects of pretreatment with leptin (10(-8) M) on the contractile responses of rabbit clitoral corpus cavernosal smooth muscle strips. The effects of leptin were assessed on precontraction induced by phenylephrine (PE; 10(-9)-10(-4) M) and KCl (35-140 mM). We also examined the effect of leptin on relaxation induced by acetylcholine (ACh; 10(-9)-10(-4) M), verapamil (10(-10)-10(-6) M), and sodium nitroprusside (10(-9)-10(-4) M) in PE-precontracted (10(-5) M) strips. RESULTS: Leptin enhanced ACh-induced relaxation in PE-precontracted strips. L-NAME pretreatment significantly reduced the effect of leptin on ACh-induced relaxation, whereas L-arginine potentiated the effect of leptin. Leptin decreased the KCl-induced contractile responses. Leptin increased verapamil-induced relaxation responses. The relaxation effects of leptin on KCl-induced contraction were inhibited by 10(-5) M methylene blue and L-NAME pretreatment. CONCLUSIONS: A high concentration of leptin enhances ACh-dependent relaxation in clitoral cavernosal smooth muscles. These relaxation effects of leptin may occur through an NO-dependent mechanism and voltage-dependent calcium channel blockade.

Relation of Resistin to Prostate Cancer Differentiation and Aggressiveness

PURPOSE: Because insulin resistance may be related to prostate cancer (PCa) initiation and progression, and adipokines target preneoplastic cells, leading to activation of signaling cascades that can promote aberrant cellular proliferation and transformation to a malignant phenotype, we hypothesized that increased resistin protein in prostate epithelial cells might underlie the association between PCa and insulin resistance. MATERIALS AND METHODS: In this study, we investigated the intensity of prostate epithelial resistin expression by immunohistochemical staining in 67 patients with PCa and 26 patients with benign prostatic hyperplasia (BPH). The body mass index (BMI) and age of the groups were similar. Patients with PCa were stratified into 3 groups according to the spread of the disease as organ-confined, locally advanced, or metastatic disease and according to the grade. RESULTS: The intensity of prostate epithelial resistin expression and the mean prostate-specific antigen (PSA) were significantly greater in the PCa group than in the BPH group. Additionally, according to progression of PCa, mean PSA, mean age, and the intensity of resistin expression were significantly increased. With higher Gleason score of PCa, age and the intensity of resistin expression were significantly increased. CONCLUSIONS: The results of our study reveal that the intensity of prostate epithelial resistin expression is higher in those with PCa than in those with BPH. A positive association was found between the histologic grade and stage of PCa and the intensity of resistin expression.

Eta-1/Osteopontin Genetic Polymorphism is Associated with Urolithiasis in Koreans / 대한비뇨기과학회지

PURPOSE: Osteopontin(OPN) is one of the major non-collagenous bone matrix proteins produced by osteoblasts and osteolclasts, and it is also involved in the pathogenesis of urolithiasis. Single nucleotide polymorphisms(SNPs), as a tool for searching for the genetic markers of disease, have a large role in investigating the genetic markers of complex human diseases. The aim of this study is to investigate the association with this SNP at position nucleotide 9250(C-->T) in the OPN gene and the susceptibility to urolithiasis. We also compared the allele frequency of Koreans with those of Americans and Japanese. MATERIALS AND METHODS: A total of 161 urolithiasis patients and 104 healthy controls were studied. The SNPs located at position 9520 in the OPN gene were genotyped using restriction fragment length polymorphism(RFLP). The wild-type sequence contains a C while the polymorphism variant is a T(C-->T), which results in the appearance of an Alu I restriction site. RESULTS: The gene frequencies of C/C, C/T and T/T at position 9250 on the Eta-1/osteopontin gene in urolithiasis patients were 10.6%, 36.6% and 52.8%, respectively, compared with 6.7%, 27.9% and 65.8%, respectively, in the controls(p>0.05). The allele frequencies of C and T at this position in the urolithiasis patients were 28.9 and 72.1, respectively, whereas those in the controls were 20.7 and 79.3, respectively,(p<0.05). The allele frequencies found in the present study were compared with those coding SNPs described in the USA database; 60 and 39(USA) vs 20.7 and 79.3 (Korea), respectively(p<0.05). CONCLUSIONS: Those findings suggest there is no association of with Eta-1/osteopontin genetic polymorphism, but the allele frequencies were significantly associated with urolithiasis patients. We also observed difference of allele frequencies in our controls and in the USA controls and these differences may be caused by a difference in the incidence of urolithiasis patients between the two countries.