| Abstract: | An in vitro system using the minces of placental villi from first trimester human pregnancy (6-10 weeks) has been validated to examine the effect of addition of GnRH and its analogues on hCG secreted into the medium. Addition of low concentration of GnRH or its analogues (1 X 10(-8) M to 1 X 10(-6) M) resulted in an increase in the quantity of hCG in the medium, while addition of high concentrations of GnRH resulted in an inhibitory effect. Of the analogues tested, Buserelin was highly effective in exerting an inhibitory effect. A significant increase in 35S-methionine incorporation into immunoprecipitable hCG was noticed in the presence of GnRH. These results suggests that GnRH stimulates both synthesis and secretion of hCG by first trimester human placenta. |
