Peripheral and ovarian vein plasma levels of 20alpha-dihydroprogesterone in women with normal menstrual cycles.
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Biomedical subjects
Publications and source records attributed to A Bompiani.
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4 cases of normal pregnancies associated with low estriol excretion and resulting in healthy infants are described, in which by in vitro studies on the placentas a steroid 3-sulfatase deficiency was found in 3 cases and a lack of activity of the aromatizing system was found in the 4th case. A reduced activity of the aromatizing system was also shown in one of the cases affected by steroid 3-sulfatase defect. The placental 3 beta-hydroxysteroid dehydrogenase, delta 4,5-isomerase system was measured in 3 cases and results were normal. The repetition of the specific lack of steroid 3-sulfatase was observed in 2 successive pregnancies of the same patient (case T.C.). It is interesting to note that, at variance with other reports, this patient delivered 2 fetuses, both female.
The activities and contents of microsomal mono-electron carriers (NADPH-cytochrome c reductase, NADH-cytochrome b5 reductase, cytochrome P-450 and cytochrome b5) in the liver of 160 pregnant rabbits and their response to phenobarbital (PB) administration were found to be different to that of non pregnant animals and to vary depending on the period of gestation. In fetal liver and in placenta the activities and contents of mixed function oxidase system enzymes are very low and increase from the mid-gestation up to the term of pregnancy. PB has either effect or decreases the enzyme levels. The variations of enzyme content and activity in maternal liver and the different response to PB are related to the hormonal modifications of pregnancy. The behaviour of mono-electron carriers in fetal liver can be related to the process of maturation of this organ. The effect of PB can be due to the interference of the drug with steroid metabolism. The behaviour of mixed function oxidase system enzymes in placenta can be related to the processes of maturation and ageing of organ.
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Total tissue water of rabbit plancenta decreases by 18% between the 9th day and the end of gestation. In the same period intracellular water decreases by 40% and the extracellular compartment swells. Total tissue sodium and chloride content increase by 34% and 27% respectively from the 16th to the 33rd day while potassium decreases by 30%. The intracellular concentration of these ions does not vary greatly during gestation. Moreover the total tissue magnesium content decreases by about 23% at the end of gestation while its intracellular concentration does not show marked changes. Calcium content of rabbit placenta substantially increases during gestation and intracellular calcium shows a fivefold increase from the 16th to the 33rd day of gestation. The results are discussed in terms of relation between water and ion content and placental tissue growth and aging.
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The authors have incubated, in vitro, estrous rabbit endometrium with 3H-leucine and pseudopregnant rabbit endometrium with 14C-leucine. By the double-labeling technique and the use of the 14C:3H ratio, it was shown that blastokinin (BKN) is neosynthesized in vitro and that this neosynthesis probably also affects other protein components. By ion exchange chromatography of the supernatant of the pseudopregnant endometrium and previously purified BKN, it was possible to confirm the in vitro biosynthesis and to exclude interfering phenomena. Time dynamics showed that biosynthesis was more marked between the 18th and 24th hours of incubation.
The activities and the content of enzymes involved in mixed function oxidase systems (cytochromes P-450 and b5, NADPH-cytochrome c reductase and NADH cytochrome b5 reductase) in microsomes from 114 human placentae were found to increase from the 34th up to the 38th-39th week of gestation and later to decrease until the 43rd week. Such a process can be related to the following: (i) the phospholipid content of microsomal membranes; (ii) the protein synthesis possibly induced by steroids such as androstenedione and testosterone.
The Authors describe the laparoscopic aspects of spontaneous human ovulation and correlate it with the evaluation of basal body temperature, the total urinary oestrogens, pregnanediol and urinary LH and some hematic values of 17-beta-estradiol, 17-alpha-Hydroxyprogesterone and rogesterone. They find that the rise in temperature and the oestrogenuria peak precede ovulation by some hours in the great ovulation by sompe hours in the great majority of cases. They analyze the validity of the other parameters studied, and show a relatively constant behavior, with regard to ovulation, in the mean evaluation of several cases. In the individual analysis, on the contrary, this relation is difficult to find and less significant. The Authors stress the importance of comparing the physico-chemical evaluations with the biological phenomenon of ovulation directly ascertained by means of laparoscopy.
The properties of the enzyme oestradiol-17 beta dehydrogenase from human umbilical cord serum have beem compared with those of oestradiol-17 beta dehydrogenase present in the maternal peripheral blood. On the basis of studies on stability, specificity, optimum pH, rate of enzymic reaction and Km determinations it can be concluded that oestradiol-17 beta dehydrogenase in the umbilical cord arteries has an activity between 5 and 15 times higher than in the umbilical cord vein and about 65% of the activity of the enzyme present in the maternal peripheral blood. The present results strongly suggest that in pregnancy the enzyme oestradiol-17 beta dehydrogenase is elaborated not only by the placenta but also by the foetus.
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The authors studied the binding of steroids with Blastokinin (BKN). They confirm that progesterone is the steroid that has a greater affinity for BKN than estradiol or testosterone; the latter is hardly bound to the protein at all. They also show that the presence of estradiol interferes with the formation phase of the BKN-progesterone complex, while testosterone does not. When the BKN-progesterone complex is already formed, a release of the progesterone occurs only when there is a double concentration of estradiol. The biological importance of this phenomenon is briefly discussed.
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