[PDF] The relative importance of the oligosaccharide units in human chorionic gonadotropin (CG) for LH/CG receptor activation in rat Leydig cells and mouse Leydig tumor cells. | Semantic Scholar (2024)

The results exemplify a simple and efficient method for creating deglycosylated hCG and provide the most direct evidence for the importance of Asn-linked carbohydrate chains in maintaining hCG bioactivity.

It is discovered that basal levels of steroidogenesis in MA-10 cells were considerably higher than previously estimated and dibutyryl cAMP-stimulated steroid production was linear over more than 13 h, in contrast to previous findings that measured progesterone levels.

The crescendo of events leading first to ovulation and subsequently to birth is orchestrated by a broad repertoire of hormones, and the predominant role for glycosylation appears to be the conferment of increased solubility to endocrine molecules, either during their manufacture or by modulating circulatory half-life.

It is likely that gonadotropin-stimulated progesterone formation is regulated by a pathway that includes PKA and StAR, and this process is downregulated by ERK, due to attenuation of StAR expression.

It is suggested that TGF-α biphasically regulates mouse placental lactogen-II secretion through regulation of mPL-II gene expression after midpregnancy.

It is likely that gonadotropin-stimulated progesterone formation is regulated by a pathway that includes PKA and StAR, and this process is down-regulated by ERK, due to attenuation of StAR expression.

The “heteromer hypothesis” explains how opposite death and life signals are delivered by gonadotropin receptors and other membrane partners, mediating steroidogenesis, apoptotic events, and the maturation of the dominant follicle.

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Studies with MA-10 cells provide unequivocal evidence that the presence of antennary sugars in LH and hCG (and perhaps in other similar hormones such as follicle-stimulating hormone and thyroid- Stimulating hormone), is essential for signal transduction.

The inhibition by the GP of hCG seems to be restricted to the LH/hCG-stimulatable AC system because the same dosage of h CG GP which inhibited the rat luteal AC system did not have any effect on the rat hepatocyte AC system when coincubated with glucagon or on NaF-stimulated activity in lutesal membranes.

Some changes in the steroidogenic pathway are revealed, including an increase in the ability of the cultured cells to synthesize 20 alpha-dihydroprogesterone (20 alpha-hydroxypregn-4-en-3-one).

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