Is maternal progesterone actually independent of the fetal steroids?

Další autoři:	Hill, Martin, 1962- Pařízek, Antonín, 1959- Jirásek, Jan Evangelista, 1929-2019 Jirkovská, Marie, 1954- Velíková, M. Dušková, Michaela Klímková, M. Pašková, Andrea Žižka, Zdeněk Moravská, Alexandra Koucký, Michal Kalousová, Marta, 1974- Stárka, Luboslav, 1930-2022
Jazyk:	angličtina
Předmět:	steroidy progesteron práce steroids progesterone labor články journal articles 20α-dihydroprogesterone plasma metabolome GC-MS
Druh dokumentu:	Kniha
Abstrakt:	Abstract: a1_Progesterone and estradiol are the foremost steroid hormones in human pregnancy. However, the origin of maternal progesterone has still not been satisfactorily explained, despite the generally accepted opinion that maternal LDL-cholesterol is a single substrate for placental synthesis of maternal progesterone. The question remains why the levels of progesterone are substantially higher in fetal as opposed to maternal blood. Hence, the role of the fetal zone of fetal adrenal (FZFA) in the synthesis of progesterone precursors was addressed. The FZFA may be directly regulated by placental CRH inducing an excessive production of sulfated 3β-hydroxy-5-ene steroids such as sulfates of dehydroepiandrosterone (DHEAS) and pregnenolone (PregS). Due to their excellent solubility in plasma these conjugates are easily transported in excessive amounts to the placenta for further conversion to the sex hormones. While the significance of C19 3β-hydroxy-5-ene steroid sulfates originating in FZFA for placental estrogen formation is mostly recognized, the question “Which maternal and/or fetal functions may be served by excessive production of PregS in the FZFA?“ - still remains open. Our hypothesis is that, besides the necessity to synthesize de novo all the maternal progesterone from cholesterol, it may be more convenient to utilize the fetal PregS. The activities of sulfatase and 3β-hydroxysteroid dehydrogenase (3β-HSD) are substantially higher than the activity of cytochrome P450scc, which is rate-limiting for the placental progesterone synthesis from LDL-cholesterol. However, as in the case of progesterone synthesis from maternal LDL-cholesterol, the relative independence of progesterone levels on FZFA activity may be a consequence of substrate saturation of enzymes converting PregS to progesterone.
Databáze:	Katalog Knihovny AV ČR
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