Corpus luteum function in early pregnancies is primarily determined by the rate of change of human chorionic gonadotropin levels

Article Abstract:

After the female egg has been released from its follicle during ovulation, the corpus luteum is formed from the follicular remnants; it is this structure that manufactures progesterone, needed for the maintenance of pregnancy should fertilization occur. Progesterone secretion is gradually taken over by the placenta until, by eight and one half weeks of gestation, the placenta can supply the fetus with all the progesterone it needs. To learn more regarding the development and function of the corpus luteum in these early weeks, progesterone blood levels were analyzed for 70 women, 35 of whom had undergone ectopic pregnancy. In such cases, the embryo implants in a site other than the uterus, and progesterone levels are lower than normal. Of specific interest was whether ectopic pregnancy could be diagnosed by progesterone levels. The remaining subjects had had normal intrauterine pregnancies (21) or miscarriages (14). Blood had been drawn and stored at two- or three-day intervals; for this study, the concentrations of progesterone and hCG (human chorionic gonadotropin, secreted by early placental tissue) were measured. When administered during early pregnancy, hCG prolongs the life of the corpus luteum, but the mechanisms of this regulation have not been completely determined. Results showed that the rate of increase of hCG in ectopic pregnancies was slower than in intrauterine pregnancies, and the rate for miscarriages lay between the other two rates. The same relationships were found for progesterone levels, with the lowest values for ectopic pregnancy. Patients' progesterone levels were correlated with the rate of increase of hCG levels, but no consistent correlation between levels of the two hormones was found. The results suggest that the rate of change of hCG levels, rather than their absolute values, may control corpus luteum function. They also imply that serial progesterone determinations, rather than just one test, should be used to decide whether a pregnancy is ectopic, a situation that requires immediate medical intervention. (Consumer Summary produced by Reliance Medical Information, Inc.)

Diagnosis, Measurement, Pregnancy, Pregnancy, Ectopic, Ectopic pregnancy, Progesterone

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The role of p53 tumor suppressor gene and bcl-2 protooncogene in rat corpus luteum death

Article Abstract:

Proteins coded by the genes p53 and bcl-2 that are produced in the ovulating ovarian follicle do not seem to regulate one another during observed programmed cell death. Corpus luteal cells from 26 young female rats stimulated to ovulate were sampled 8, 10, 12, and 14 days after ovulation. Gene fragments characteristic of programmed cell death were observed in all samples. The amount of p53 protein product, an inhibitor of cell growth, decreased during the study period. The amount of bcl-2 protein product, a promotor of cell growth, remained constant during the study period and then significantly decreased on day 14.

Genetic aspects, Cell death, Tumor suppressor genes, Proto-oncogenes

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Methotrexate effects on trophoblast and the corpus luteum in early pregnancy

Article Abstract:

The drug methotrexate may induce abortion by destabilizing the early embryo and preventing it from attaching to the uterus. Researchers measured blood levels of human chorionic gonadotropin and progesterone in 20 pregnant women who took methotrexate to induce abortion. Human chorionic gonadotropin levels did not rise as high as in normal pregnancies. This chemical is produced by the embryonic tissues and in turn stimulates the ovarian follicle to produce progesterone. However, progesterone levels decreased in some women but increased in others, indicating that methotrexate may act alone to destabilize the embryo.

Abortion, Trophoblast, Trophoblasts, Methotrexate

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