LAUSR

In bovine luteal cells, progesterone can directly affect its own synthesis by increasing the activity of 3β-HSD. The effect of progesterone on its own secretion coincides with increased expression of the genes for 3β- HSD, StAR, and cytochrome P450scc. Therefore, progesterone regulates its own synthesis by affecting the activity of the enzymes that take part in luteal steroidogenesis, and also by affecting the expression of the genes for these enzymes. The aims of this study were: (a) to determine whether progesterone affects the expression of the gene for its own receptor, thereby affecting its own synthesis; and (b) to determine whether oxytocin and noradrena - line affect the expression of the genes for the oxytocin receptor (OT-R), the progesterone receptor (P4-R), and the β 2 receptor (β 2 -R), thereby regulating luteal steroidogenesis. Two populations of luteal cells were used in the present study: from 6 th -10 th and 11 th -16 th days of the estrous cycle, which were isolated from luteum (CL)