| Abstract: | The secretion in vitro of HCG and proteins was studied in fragments of placenta from women in the first trimester of pregnancy by a pulse-chase system. A 10-min pulse with [3H]leucine was used. It was concluded that the approximate half-time of release of HCG was 150 min. Proteins precipitable with trichloroacetic acid had a bi-exponential pattern, the half-times of release being 100 and 270 min. These rates of release indicate that the HCG produced by the early placenta was rapidly passed into the circulation rather than stored. |
