Altered striatal vulnerability to 3-nitropropionic acid in rats due to sex hormone levels during late phase of brain development.

Systemic administration of 3-nitropropionic acid (3-NPA) leads to a shortage of cellular ATP and induces striatum-specific lesions that resemble Huntington's disease. Gender differences, in terms of vulnerability of striatum to 3-NPA, have been shown in male rats. The goal of the present study was to determine whether changes in sex hormone levels during the critical period of sexual differentiation (E17-P4) influence striatal vulnerability to 3-NPA. An androgen receptor antagonist, flutamide, or an aromatase-inhibitor, fadrozole hydrochloride, which block conversion of testosterone to estradiol, were administered to embryonic rats during E17-E20 or E18-E20, respectively, with subsequent 3-NPA (20mg/(kg day) for 2 days) treatment during adulthood (8-9 weeks old). Motor behavior and histological changes (IgG exudation due to blood-brain barrier dysfunction and glial fibrillary acidic protein immunoreactivity) were assessed. Treatment with flutamide significantly decreased the 3-NPA-induced motor behavior in male rats, while administration of fadrozole hydrochloride increased atypical motor behavior in female rats. IgG exudation, as well as decreased glial fibrillary acidic protein reactivity, was observed in animals with motor defects. Flutamide decreased testosterone levels in male rats, while fadrozole hydrochloride increased testosterone levels in female rats. These results suggest that prenatal modulation of sexual hormonal levels greatly influences vulnerability to 3-NPA during adulthood and directly correlates to serum testosterone levels.

Estrogen blocks 3-nitropropionic acid-induced Ca2+i increase and cell damage in cultured rat cerebral endothelial cells.

Systemic administration of 3-nitropropionic acid (3-NPA, a mycotoxin) induces brain damage accompanied by disturbance in the blood-brain barrier (BBB). Since the endothelial cells are important components of the BBB and the first target of a systemic intoxication, in the present study, the effect of 3-NPA on primary cultured rat brain endothelial cells (rBECs) was examined by studying intracellular Ca(2+) ([Ca(2+)](i)) response using imaging techniques with fura-2. rBECs were prepared using a method of Kis et al. [Eur. J. Pharmacol. 368 (1999) 35-42] and Szabo et al. [Neurobiology 5 (1997) 1-16]. Almost all cells were immunoreactive to antibody against the factor VIII-related antigen (von-Willebrand factor). They showed a typical dose-dependent increase of [Ca(2+)](i) in response to ATP or bradykinin. Low concentrations of 3-NPA (1.7 mM, 3.4 mM) caused no changes, and a medium concentration (6.8 mM) increased the [Ca(2+)](i) gradually and progressively, and the increase was reversed incompletely back to the resting level after washing. A high concentration (13.6 mM) increased the [Ca(2+)](i) irreversibly. These elevations of [Ca(2+)](i) were absent in a Ca(2+)-free medium. In endothelial cells treated with 17beta-estradiol (above 10(-5) M) or with a selective estrogen receptor modulator, tamoxifen (5 x 10(-7) M), no elevation of [Ca(2+)](i) was observed with 3-NPA treatment. The response to ATP was impaired after application of 3-NPA, but it was preserved by cotreatment with 17beta-estradiol or tamoxifen. An estrogen receptor antagonist ICI 182,780 inhibited these effects by 17beta-estradiol or tamoxifen. Lysosomal neutral red uptake and TUNEL experiments revealed the necrotic but not apoptotic cell death at least in this acute stage. Data indicate that a medium to high concentration of 3-NPA induces damage on rBECs as revealed by an accumulation of [Ca(2+)](i), but the damage was protected by cotreatment with 17beta-estradiol or tamoxifen, suggesting that estrogen may be protective for the brain vascular damage via estrogen receptor.

Spermatogenesis, fertility and sexual behavior in a hypospadiac mouse model.

PURPOSE: Administering of flutamide to pregnant mice causes hypospadias in male offspring. We investigated spermatogenesis, fertility and sexual behavior in this hypospadiac mouse model. MATERIALS AND METHODS: Male offspring exposed to flutamide during the embryonic period were divided into hypospadiac group 1 and normal external genitalia group 2. Control group 3 consisted of male offspring not exposed to flutamide. We analyzed the spermatogenesis, epididymides sperm motility, in vitro fertilization rate and sexual behavior of each mouse. RESULTS: There were no significant differences in the weight of the testes or mean seminiferous tubular diameter in the groups. The number of apoptotic germ cells per unit area was not significantly different in the 3 groups. In groups 1 to 3 there were no significant differences in the mean epididymides sperm motility rate plus or minus standard deviation (62.6% +/- 10.0%, 57.2% +/- 7.0% and 67.0 +/- 7.6%) or in the in vitro fertilization rate (52%, 48% and 48%, respectively). However, there were significant differences in groups 1 to 3 in mean mounting frequency (0, 29 +/- 4.0 and 12.4 +/- 4.5 times per hour) and mean intromission frequency (0, 24.4 +/- 3.5 and 3.8 +/- 1.5 times per hour, respectively). Females coupled with group 1 or 2 male mice did not achieve pregnancy. CONCLUSIONS: These results suggest that spermatogenesis, sperm motility and fertilization in vitro were unaffected in hypospadiac mice but sexual motivation and arousal were deficient.