First trimester villous placenta has high prorenin and active renin concentrations

Article Abstract:

Active renin and prorenin concentration in the placental villi appears to decline markedly from early to late pregnancy. These compounds are part of a system that modulates blood vessel growth and proliferation and that has local influences on hormone secretion. Placental villi were obtained from placentas from first trimester abortions and from placentas at term birth. Amounts of prorenin and active renin were measured by radioimmunoassay as were amounts of human chorionic gonadotropin (hCG). Prorenin was found in villous tissue in amounts nearly 200-times higher in the first trimester than at birth. The proportion of active renin to prorenin was also higher in the first trimester. HCG is known to stimulate prorenin synthesis in the ovary. Because hCG follows this same pattern within the villi, it is speculated that it may play a similar role there.

Measurement, Prolactin, Chorionic gonadotropin, Chorionic gonadotropins, Renin-angiotensin system

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Augmentation of polynuclear aromatic hydrocarbon metabolism of human placental tissues of first-trimester pregnancy by cigarette smoke exposure

Article Abstract:

Women who smoke during the first trimester of pregnancy may increase the risk of abnormalities in their unborn child. Exposure to cigarette smoke may increase the metabolism of polynuclear aromatic hydrocarbons by the placenta. Polynuclear aromatic hydrocarbons are substances found in high concentrations in cigarette smoke that can be metabolized to form different toxic substances. A study compared the metabolism of polynuclear aromatic hydrocarbons by first-trimester placental tissue from smokers and nonsmokers. The metabolism of polynuclear aromatic hydrocarbons was higher in the placental tissue from smokers than in placental tissue from nonsmokers. One enzyme involved in the metabolism of polynuclear aromatic hydrocarbons was only found in placental tissue from smokers.

Hydrocarbons, Cigarette smoke

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Syncytiotrophoblastic fragments in first-trimester decidual veins: evidence of placental perfusion by the maternal circulation early in pregnancy

Article Abstract:

According to an analysis of uterine tissue specimens taken from an abortion, the mother's blood begins to circulate through the placenta during the first trimester. Researchers detected dilated veins in the tissue samples as well as cells from the fetus.

Blood circulation

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