Costus afer leaf extract protects against testicle damage caused by cyclosporine A in adult male Wistar rats through an antioxidant mechanism

Cyclosporine A is one of the most widely used drugs in organ transplant and oncology patients. But its use is accompanied by many toxicities. This study aimed to investigate the possible protective effect of Costus afer (C. afer) leaf extract on cyclosporine A-induced testicular toxicity. This study was carried out on 40 adult male Wistar rats were divided into four groups: control, C. afer, cyclosporine A and cyclosporine A+ C. afer groups. The investigations include genital weight, sperm count and characters, serum luteinising hormone (LH) and testosterone, testicular tissue contents of reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx) and lipid peroxidation (MDA). Besides, a histopathological examination of testicular tissue stained with haematoxylin and eosin (H & E) was performed. Cyclosporine A+ C. afer group showed a significant increase in the genital weight, serum testosterone, sperm count, motility and viability. Besides, the extract significantly decreased testicular content of MDA and increased SOD, CAT and GSHPx. C. afer coadministration significantly decreased serum LH and sperm abnormalities and protected against testicular histopathological alterations. The extract showed a protective effect against testicular toxicity associated with cyclosporine A and that was through an antioxidant mechanism.     

Aldosterone and testosterone: two steroid hormones structurally related but with opposite electrophysiological properties during myocardial ischemia–reperfusion

Steroid hormones appear to be a key factor in the gender differences in the rates and severity of cardiovascular diseases. Aldosterone and testosterone have typical steroid ring structure, but despite this, they demonstrate very different properties. During acute myocardial ischemia–reperfusion, the deleterious impact of aldosterone is now well established. Conversely, the electrophysiological impact of testosterone in this context remained unknown. We used female rabbit in vitro models and standard microelectrode technique including right ventricle mimicking the ‘border zone’ existing between normal and ischemic/reperfused areas and isolated right ventricle experiments to assess the acute electrophysiological impact of both aldosterone and testosterone. During ischemia–reperfusion, acute superfusion of 10 and 100 nmol/L testosterone decreased normoxic and reperfused action potential duration at 90% (APD₉₀), systematically induced conduction blocks, and decreased APD₉₀ dispersion between ischemic and nonischemic areas (from 98 ± 4 to 57 ± 7 ms and 66 ± 3 ms, for, respectively, testosterone 10 and 100 nmol/L, P < 0.05). Testosterone 10 and 100 nmol/L concomitantly decreased sustained premature ventricular contraction (PVC) occurrence (from 55 to 0%, P < 0.05). Conversely, aldosterone 10 and 100 nmol/L increased normoxic and reperfused APD₉₀, APD₉₀ dispersion, and reperfusion‐induced PVCs. Furthermore, testosterone demonstrated cycle length‐dependent effects on APD₉₀ for high heart rate, whereas aldosterone did not exhibit any significant effect compared with controls. During acute myocardial ischemia–reperfusion, acute superfusion of physiological concentrations of testosterone seemed to be anti‐arrhythmic by removing a pro‐arrhythmic substrate (APD₉₀ dispersion), inducing conduction blocks and decreasing triggered activities (PVC occurrence). Further experiments are warranted to confirm our results.     

Endogenous testosterone determines metformin action on prolactin levels in hyperprolactinaemic men: A pilot study

Metformin was found to reduce elevated prolactin levels in women but not in men. The current study was aimed at investigating whether endogenous testosterone determines the impact of metformin on lactotroph function in men. This prospective case‐control study included 28 men with recently diagnosed type 2 diabetes mellitus and mild or moderate hyperprolactinaemia, 14 of whom had low testosterone levels, while in the remaining 14 ones' testosterone levels were within the reference range. All participants received metformin (2.55‐3 g daily) for the following 4 months. Circulating levels of glucose, insulin, prolactin, testosterone, oestradiol, gonadotropins, sex hormone‐binding globulin adrenocorticotropic hormone, insulin‐like growth factor‐1, thyrotropin and free thyroid hormones were measured at the beginning and at the end of the study. Although metformin reduced plasma glucose levels and improved insulin sensitivity in both groups, this effect was stronger in participants with low testosterone levels. Only in patients with abnormally low testosterone levels, the drug decreased prolactin levels. This effect, which was accompanied by an increase in luteinizing hormone levels, was inversely correlated with baseline testosterone and calculated free testosterone levels, and positively with treatment‐induced improvement in insulin sensitivity. In both treatment groups, metformin produced a neutral effect on plasma levels of the remaining hormones. The obtained results suggest that endogenous testosterone may attenuate the impact of metformin on lactotropic cells.     

Anxious to see you: Neuroendocrine mechanisms of social vigilance and anxiety during adolescence

Social vigilance is a behavioral strategy commonly used in adverse or changing social environments. In animals, a combination of avoidance and vigilance allows an individual to evade potentially dangerous confrontations while monitoring the social environment to identify favorable changes. However, prolonged use of this behavioral strategy in humans is associated with increased risk of anxiety disorders, a major burden for human health. Elucidating the mechanisms of social vigilance in animals could provide important clues for new treatment strategies for social anxiety. Importantly, during adolescence the prevalence of social anxiety increases significantly. We hypothesize that many of the actions typically characterized as anxiety behaviors begin to emerge during this time as strategies for navigating more complex social structures. Here, we consider how the social environment and the pubertal transition shape neural circuits that modulate social vigilance, focusing on the bed nucleus of the stria terminalis and prefrontal cortex. The emergence of gonadal hormone secretion during adolescence has important effects on the function and structure of these circuits, and may play a role in the emergence of a notable sex difference in anxiety rates across adolescence. However, the significance of these changes in the context of anxiety is still uncertain, as not enough studies are sufficiently powered to evaluate sex as a biological variable. We conclude that greater integration between human and animal models will aid the development of more effective strategies for treating social anxiety.     

Do men with normal testosterone–oestradiol ratios benefit from letrozole for the treatment of male infertility?

Research question

Previous studies of aromatase inhibitors on male infertility have focused on men with low testosterone–oestradiol ratio of less than 10. Can aromatase inhibitors improve spermatogenesis in men with idiopathic male infertility with normal testosterone–oestradiol ratio?

Dutasteride in men receiving testosterone therapy: a randomised,double‐blind study

We investigate the impact of dutasteride on prostate specific antigen (PSA) and prostate volume in men receiving testosterone (T) therapy. Twenty‐three men on stable dose T therapy were randomised to receive either dutasteride or placebo for 12 months. Serum levels of PSA, T and dihydrotestosterone (DHT) and responses to the International Index of Erectile Function (IIEF) and Male Sexual Health Questionnaire (MSHQ) questionnaires were determined at baseline and at 3, 6, 9 and 12 months. Prostate volume (PV) was measured using transrectal ultrasound (TRUS) at baseline and again after 12 months. A total of 22 men (mean age 57.3) completed the study, with 11 men receiving placebo and 11 receiving dutasteride. Men receiving dutasteride had a significant decrease in PSA (?0.46 ± 0.81 ng ml^?1; P = 0.04) and in PV (?6.65 ± 11.0%; P = 0.03) from baseline over 12 months. DHT decreased significantly for men on dutasteride compared with men receiving placebo (P = 0.02). When compared with men who received placebo, men who received dutasteride demonstrated nonsignificant trends towards decreased PSA (?0.46 versus 0.21 ng ml^?1; P = 0.11), PV (?6.65% versus 3.4%; P = 0.08) and MSHQ scores (?10.2 versus 5.6; P = 0.06). Dutasteride reduces PSA and PV for men on T therapy, but perhaps less so than in men without T therapy.