INCORPORATION OF H-3 AMINO-ACIDS BY ENDOMETRIAL STROMAL CELLS DURING DECIDUALIZATION IN THE MOUSE - A AUTORADIOGRAPHICAL STUDY

The incorporation of H-3-amino acids by endometrial stromal cells was analyzed by radioautography during decidualization in the mouse. H-3-p roline was administered to 5- and 6-day pregnant mice and to virgin mi ce in estrus used as controls. H-3-tryptophane was administered to 6-d ay pregnant mice. The animals were killed 30 min. after the injection of the radioactive label. The quantitative analysis of the radioautogr ams showed that the concentration of silver grains per unit area due t o H-3-proline incorporation was higher in decidual and predecidual cel ls on the fifth and sixth day of pregnancy than in fibroblasts of virg in mice. Considering the pregnant endometrium by itself, the incorpora tion of both H-3-proline and H-3-tryptophane was higher in fully diffe rentiated decidual cells and predecidual cells than in fibroblasts of the periphery of the endometrium and involuting decidual cells. These results show a clear correlation between different endometrial regions recognized by morphological criteria and their metabolic activity. Th e data also show that different cells of the pregnant endometrium have different metabolic activities, independently of the precursor that w as used.