The effects of insulin-like growth factor-I on gonadotropin release were studied using primary culture of rat anterior pituitary cells incubated with IGF-I ( 20\ x=r eq-\ 5000 \g=m\g/l) and a hypothalamus-pituitary perifusion system, in which either the mediobasal hypothalamus-pituitary unit or the pituitary were perifused with IGF-I (20-2000 \g=m\g/l). In primary cultures of rat anterior pituitary cells, IGF-I (2000 \g=m\g/l ) caused a significant increase in the release of both LH (46% increase) and FSH (27% increase). It also caused a significant decrease in the cellular content of LH (9%) and FSH (19%). Its effects in stimulating gonadotropin release were suppressed by administration of anti IGF-I receptor antibody (1 mg/l). In the perifusion system, IGF-I (2000 \g=m\g/l ) did not affect the LH release from the hypothalamus-pituitary or pituitary alone. However, it caused a significant increase in the GnRH (10\ m=-\ 9 mol/l) stimulated LH release from perifused pituitary. These data suggest that IGF-I enhances pituitary gonadotropin release via the IGF-I receptor, but its effect on the hypothalamus was not confirmed.

The adsorption behavior of arsenic from water on spherical porous silica particles(SiMAG) covered with magnetite was investigated under batch equilibrium conditions at 303K. The specific surface area and the pH at zero point of charge of SiMAG were 540 m2/g and 4.6, respectively. Both of As(V) and As(III) were adsorbed on SiMAG The adsorption of As(V) increased with decreasing pH, while that of As(III) was slightly dependent on pH. The adsorption capacity of SiMAG towards As(V) was 0.85 mmol/g.