Effects of di(2-ethylhexyl) phthalate on gap and tight junction protein expression in the testis of prepubertal rats.

The aim of this study was to analyze whether di(2-ethylhexyl) phthalate (DEHP), a Sertoli and Leydig cell toxicant, is able to induce alterations in the expression of testicular gap and tight junction proteins. DEHP was administered by gavage (1 g/5 mL corn oil/kg body weight/day) to 25-day-old male Sprague-Dawley rats for 2 days (DEHP-27d) and control rats were treated with corn-oil vehicle for 2 days (C-27d); animals were killed 24 h after the last treatment. Testes of DEHP-27d rats showed different degrees of germ cell sloughing of seminiferous tubules (ST).

Direct effect of ghrelin on leptin production by cultured rat white adipocytes.

Objective: Because ghrelin is known to stimulate adipogenesis, we tested whether ghrelin could contribute to the maintenance of homeostasis, directly affecting rat white adipocyte leptin production.

Research Methods And Procedures: Isolated retroperitoneal adipocytes were cultured for 0.5 to 48 hours without (baseline) or with (0.

Modulatory effects of leptin on leydig cell function of normal and hyperleptinemic rats.

Neonatal L-monosodium glutamate (MSG) administration in rats induces several neuroendocrine and metabolic disruptions. Leptin, the adipocyte product, modulates several neuroendocrine systems including the hypothalamic-pituitary-gonadal (HPG) axis in mammals. The aim of the present study was to determine whether MSG-induced chronic hyperleptinemia could play any relevant role in the hypogonadism developed by male rats when examined in adulthood.

Involvement of tumor necrosis factor-alpha in the pathogenesis of autoimmune orchitis in rats.

We studied the testicular macrophages of rats with experimental autoimmune orchitis (EAO) and analyzed whether the tumor necrosis factor-alpha (TNFalpha) is involved in germ cell apoptosis and in Leydig cell steroidogenesis. The EAO was induced in adult male Sprague-Dawley rats by active immunization with testicular homogenate and adjuvants. In the experimental group, a severe orchitis was observed 80 days after the first immunization.

Role of type IV collagen in prolactin release from anterior pituitaries of male rats.

We previously demonstrated that laminin, a component of basement membranes, modulates pituitary hormone secretion. In the present study, we evaluated the effect of type IV collagen, another component of this membrane, on the release of prolactin (PRL) by anterior pituitary gland from adult male rats. Hemipituitaries were incubated for 3 h with type IV collagen or antibodies against it and PRL release was studied.

Puberty is delayed in male growth hormone receptor gene-disrupted mice.

The role of insulin-like growth factor-I (IGF-I) in the initiation of puberty and testicular function is poorly understood. Growth hormone (GH) receptor (R) gene-disrupted mice or GHR gene "knockouts" (GHR-KO) are GH resistant and IGF-I deficient. To assess whether the age of sexual maturation is affected by the absence of IGF-I, various parameters of sexual development including testicular and accessory reproductive organ weights, balanopreputial separation, germ cell development, and intratesticular testosterone levels were determined in normal and GHR-KO mice between the ages of 25 and 60 days.