| Autor: |
Thau, Rosemarie B., Lanman, Jonathan T., Brinson, Ashley O. |
| Zdroj: |
Biology of Reproduction; June 1977, Vol. 16 Issue: 5 p678-681, 4p |
| Abstrakt: |
We have recently found that in rhesus monkeys uterine vein progesterone levels declined by 75 percent during the second half of gestation, whereas maternal peripheral vein levels showed no significant change. These findings could reflect declining progesterone production in the ovary and/or placenta together with declining metabolic clearance. Alternatively, they would reflect increasing uterine blood flow as pregnancy progressed together with unchanged rates of progesterone production and metabolic clearance. Measurements of metabolic clearance rates (MCR), production rates (PR) and peripheral plasma levels of progesterone in the latter half of pregnancy showed that all three values near term (Day 151) did not differ significantly from their values at midgestation (Day 72). Lees and coworkers found a 22-fold increase in uterine blood flow in pregnant macaques as compared with non-pregnant animals. We believe that the declining uterine vein levels of progesterone in the face of undiminished PRs and MCRS near term reflect an increase in uterine blood flow during pregnancy, as demonstrated by others, delivering to the peripheral circulation an unchanged amount of progesterone in an increasing volume of blood and therefore at declining concentrations. |
| Databáze: |
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