A superfusion system for improved short-time cultivation of human placental tissue: Investigations on choriogonadotrophin secretion

Merz, W.E.; Erlewein, C.

doi:10.1016/s0143-4004(86)80042-x

Cited by 2 publications

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“…In baboons, application of GnRH superagonists, antagonist or antisera against GnRH interferes with the serum levels of baboon chorionic gonadotropin and progesterone and induces a disturbance of the pregnancies or their termination (Das et al, 1985;Kang et al, 1989). Placental GnRH stimulates hCG biosynthesis and secretion by a Ca2-mediated process When a single GnRH pulse in the nanomolar range is applied in a superfusion culture of first trimester placenta the tissue responds with an acute relase of hCG (Merz and Erlewein, 1986). Two GnRH pulses in an interval of 24 h induced a higher secretion rate as well as higher a-and 3mRNA levels .…”

Section: Biosynthesis Of Hcgmentioning

confidence: 99%

“…-y-Aminobutyric acid Licht et al, 1992a, b. (GABA) Glucocorticoids Wilson and Jaward, 1982;Akerbiom et al, 1988. Gonadoliberin (GnRH) Takemori et al, 1981;Haning et al, 1982;Bützow, 1982;Merz and Hilf, 1985;Merz and Erlewein, 1986;Suer-Khodr et al, 1986;Petraglia et al, 1989;Barnea and Kaplan, 1989;. Inhibin Petraglia et al, 1989Petraglia et al, 1987;Mersol-Barg et al, 1990.…”

Section: Biosynthesis Of Hcgmentioning

confidence: 99%

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The primate placenta and human chorionic gonadotropin

2009

Exp Clin Endocrinol Diabetes

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In the primate placenta various peptide and proteohormones are synthesized which control growth and development of the fetus as well as the exchange of nutrients and metabolic products between the mother and the fetus. In humans, maintenance of pregnancy in the first trimester depends on the synthesis of the bioactive glycoprotein hormone human chorionic gonadotropin (hCG). It is expressed in placenta by the syncytiothrophoblast of early pregnancy. In cell culture, hCG production seems to mark a certain step in the process of differentiation of cytotrophoblasts and choriocarcinoma cells. It is neither understood how hCG synthesis is initiated and maintained at the beginning of gestation nor what control mechanisms are responsible for the down-regulation of the synthesis at the end of the first trimester. Besides a long list of various other substances which have been described to act as intrinsic placental stimulators of hCG biosynthesis, gonadoliberin and gamma-aminobutyric acid seem to play an important role. This establishes to some extent an analogy to the regulation of gonadotropin synthesis in the central nervous system. Recently, a full-length form of functional LH/hCG receptors of approximately 80 kD has been found in term placenta suggesting autoregulation as a regulatory principle of hCG biosynthesis. In the first trimester placenta as well as in choriocarcinoma cells a truncated form (50 kd) of LH/hCG receptors seems to exist. In these cases, exogenous hCG was unable to down-regulate its own synthesis. The carbohydrate moiety of hCG influences folding, subunit assembly, circulatory half-life, receptor interaction and biological response. A surplus of glycosylation may prevent subunit assembly. Experimental deglycosylation induces a different conformation of hCG, which partly acquires antagonistic properties. Recent results indicate that cAMP, which increases transcription and mRNA stability, also expands the N-glycosylation capacity and thus may accomplish an over-all coordination of hCG biosynthesis including post-translational events.

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Section: Biosynthesis Of Hcgmentioning

confidence: 99%