| Abstract: | ![]()
Human corpora lutea of pregnancy obtained at 5 to 11 weeks of gestation were incubated in vitro in the presence of various concentrations of human chorionic gonadotropin (hCG) and prostaglandin F2alpha (PGF2alpha). Progesterone (P) and 17beta-estradiol (E2) released into the medium during incubation were measured by radioimmunoassay. Pieces of the corpora lutea were also examined ultrastructurally before and after incubation. Release of P and E2 into the medium was significantly increased by the addition of hCG and PGF2alpha in some cases. However, the response to hCG and PGF2alpha appeared to vary according to the age of the corpus luteum. Ultrastructurally, the lutein cells were well maintained with respect to the appearance of the smooth endoplasmic reticulum and mitochondria after 120-min incubations. On the basis of these observations, the following conclusions have been reached: 1) This incubation system seems to be suitable for investigating the direct effects of chemicals on lutein cells in vitro. 2) Both hCG and PFG2alpha directly stimulate steroidogenesis in the human corpus luteum of pregnancy, demonstrating their luteotropic actions in vitro. 3) Observed variations in P and E2 secretion might have been due to the different activities of aromatizing enzymes at different stages of gestation. |
