Paterson J Y, Harrison F A, Sheldrick E L, Heap R B
J Reprod Fertil. 1983 Sep;69(1):81-90. doi: 10.1530/jrf.0.0690081.
When [3H]progesterone is infused intravenously into ewes, blood 20 alpha-dihydroprogesterone (20 alpha-diHP) becomes labelled and the changes in [3H]20 alpha-diHP activity with time are clearly related to that of [3H]progesterone. Concentrations of 20 alpha-diHP in blood have now been estimated for these experiments. During the infusion, the specific radioactivity of 20 alpha-diHP at steady state was only 53% of the specific radioactivity of progesterone, indicating that 20 alpha-diHP was produced other than by C-20 reduction of secreted progesterone. The change in blood concentration of 20 alpha-diHP during pregnancy in ewes suggests that the placenta is its source. [3H]20 alpha-dihydroprogesterone was infused into pregnant ewes and the specific radioactivity of 20 alpha-diHP measured during and after infusion. Together with information from earlier experiments when [3H]progesterone was infused, there is now sufficient data to estimate, without constraint, the parameters of a four-pool model describing the distribution and metabolism of progesterone and 20 alpha-dyhydro-progesterone in sheep.
当将[³H]孕酮静脉注入母羊体内时，血液中的20α-二氢孕酮（20α-diHP）会被标记，且[³H]20α-diHP活性随时间的变化与[³H]孕酮的变化明显相关。现已针对这些实验估算了血液中20α-diHP的浓度。在注入过程中，稳态时20α-diHP的比放射性仅为孕酮比放射性的53%，这表明20α-diHP并非仅通过分泌的孕酮的C-20还原产生。母羊怀孕期间血液中20α-diHP浓度的变化表明胎盘是其来源。将[³H]20α-二氢孕酮注入怀孕母羊体内，并在注入期间及之后测量20α-diHP的比放射性。结合早期注入[³H]孕酮时的实验信息，现在有足够的数据来无限制地估算描述绵羊体内孕酮和20α-二氢孕酮分布及代谢的四池模型的参数。
