Fenvalerate, A Pyrethroid Insecticide, Adversely Affects Sperm Production and Storage in Male Rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The aim of this study was to investigate the potential estrogenic activity of fenvalerate by examining reproductive and fertility capabilities in Wistar rats. Adult male animals were treated for 30 d with 20 or 40 mg/kg/d fenvalerate or corn oil (vehicle) by oral gavage. Further, a possible estrogenic activity of fenvalerate (0.4, 1, 4, 8, or 40 mg/kg) was tested after a 3-d treatment of immature female rats using the uterotrophic assay. Exposure to the higher dose of fenvalerate was toxic to testis and epididymis as shown by a decrease in the absolute weights and sperm counts in both organs. Although the sperm counts were reduced, the fertility and sexual behavior were similar in control rats and rats treated with 40 mg/kg pesticide. Fenvalerate did not exert estrogenic activity in vivo at the tested doses. Data suggest that fenvalerate treatment in this study failed to compromise fertility, possibly due to enhanced reproductive capacity in rodents compared to humans.712315501558Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [02/09455-6, 04/08627-3

Reproductive effects in male rats exposed to diuron

Diuron is a ureic herbicide considered to have very low toxicity. The present study evaluated several aspects of reproductive toxicity of diuron in adult male rats. Diuron was diluted in corn oil and administered by oral gavage to groups of 18-20 rats at doses of 0, 125 or 250 mg/kg per day for 30 days; the control group received only the corn oil vehicle. At the end of the treatment period, approximately half the animals from each group were assigned to one of two terminal assessment lines: (1) reproductive organ, liver and kidney weights; measurement of diuron concentrations in liver and kidney; plasma testosterone determinations; evaluation of daily sperm production per testis; sperm number and sperm transit time in the epididymis; or (2) sexual behavior assessment during cohabitation with a receptive female; fertility and pregnancy outcome after natural mating; testicular, epididymal, kidney and liver histopathology; sperm morphology. After 30 days of oral diuron treatment, there were no treatment-related changes in body weights, but dose-related diuron residues were detected in the liver of all treated rats and absolute and relative liver weights were increased in both groups. There were no statistically significant differences between the treated and control groups obtained in plasma testosterone concentrations, or in parameters of daily sperm production, sperm reserves in the epididymis, sperm morphology or measured components of male sexual behavior. On the other hand, the number of fetuses in the litters from diuron-treated rats was slightly smaller than litters from control rats. Therefore, although the results did not indicate that diuron exposure resulted in direct male reproductive toxicity in the rat, they suggest that additional studies should be undertaken to investigate the possible effects on fertility and reproductive performance. (c) 2006 Elsevier Inc. All rights reserved.23110611

Ejaculatory dysfunction in streptozotocin-induced diabetic rats: the role of testosterone

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Hyperglycemic and hypoinsulinemic states caused by diabetes mellitus are usually related to some type of sexual dysfunction, resulting in infertility in humans and experimental models, mostly due to their effects on ejaculatory function. This study aimed to evaluate the possible role of testosterone in the restoration of normal ejaculatory function in diabetic rats. Male Wistar rats were randomly allocated into 3 experimental groups: control, diabetic (streptozotocin), and diabetic with testosterone supplementation (streptozotocin plus testosterone). The following parameters were assessed at the end of the experiment: body weight, circulating testosterone levels, number of spermatozoa ejaculated in the uterus through natural mating, and weight and in vitro isometric contractions of the vas deferens. Diabetic rats showed reduced plasma testosterone levels and ejaculatory dysfunction as observed by a lack in the spermatozoa ejaculated into the uterus of receptive females. In these diabetic rats, no difference was observed in the sensitivity of the vas deferens to norepinephrine, with or without the presence of the cocktail (cocaine plus propranolol). In spite of this, an increased sensitivity to methoxamine through the alpha(1)-adrenoceptor was observed. Testosterone supplementation did not restore these parameters to control values. We conclude that, in this experimental model, the lack of testosterone was not directly related to the diabetes-induced ejaculatory dysfunction.631130138Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq