TY - JOUR AU - SAVARD,, KENNETH AB - Abstract Progesterone synthesis in vitro and the influence of exogenous gonadotropin were studied in slices of 50 individual human corpora lutea removed at different times during the reproductive cycle. Radioactive progesterone synthesis (dpm) was assessed by incorporation of radioactivity from acetate-1-14C. The progesterone contained in corpora lutea and formed in vitro from endogenous precursors (μg) was measured spectrophotometrically by its absorption of ultraviolet light. All luteal phase corpora lutea synthesized progesterone in vitro as measured by these 2 parameters (dpm and μg). No radioactive progesterone synthesis (dpm) from acetate-1-l4C was found in 3 corpora lutea obtained after onset of menses, although 2 of the 3 specimens synthesized progesterone (μg) from endogenous precursors. Corpora lutea from all phases of pregnancy and up to 4 days post partum synthesized progesterone in vitro. The capacity for steroid biosynthesis during the post-par turn period appeared to decline gradually when steroidogenesis by post-partum corpora lutea was compared with the specimens obtained during pregnancy or at term. Corpora lutea of pregnancy, as a group, formed progesterone of higher specific activity (dpm/μg) than corpora lutea of the menstrual cycle by utilizing acetate-1-14C more efficiently (dpm/g of tissue) and forming less progesterone from endogenous precursors (μg/g of tissue). The biochemical differences between corpora lutea of the cycle and pregnancy measured in vitro appear to reflect the different hor monal milieu to which the corpora lutea were exposed in vivo. This content is only available as a PDF. Author notes This work was supported in part by Grants CA-04004, National Cancer Institute, and AM 09359, National Institute of Arthritis and Metabolic Diseases, USPHS. 1 Postdoctoral Research Fellow (1-F2-AM-29, 383 during 1965–67), National Institute of Arthritis and Metabolic Diseases, USPHS. 2 Postdoctoral Research Fellow (8-F2-HD-29,357 during 1962–64), National Institute of Child Health and Human Development, USPHS. 3 Investigator, Howard Hughes Medical Institute. Copyright © 1968 by The Endocrine Society TI - Steroid Hormone Formation in the Human Ovary: V. Synthesis of Progesterone in Vitro in Corpora Lute a During the Reproductive Cycle JF - Journal of Clinical Endocrinology and Metabolism DO - 10.1210/jcem-28-9-1249 DA - 1968-09-01 UR - https://www.deepdyve.com/lp/oxford-university-press/steroid-hormone-formation-in-the-human-ovary-v-synthesis-of-VQdbJBPOPO SP - 1249 EP - 1256 VL - 28 IS - 9 DP - DeepDyve ER -