Glycodelin or placental protein-14 is synthesized by the human secretory endometrium and decidua. It is abundantly secreted by the human endometrium under the influence of progesterone. In the uterus, glycodelin mRNA was expressed in all epithelial cells of the endometrium. In the male reproductive tract, glycodelin mRNA was distributed in all epithelial cells of the epididymis, the prostate and the seminal vesicle. However, in the testis, glycodelin mRNA was predominantly found in spermatogonia and in spermatocytes of the seminiferous epithelium (Keil et al., 1999). The exact physiological role of glycodelin is unknown but which some believed it may act as an immunosuppressive factor.Glycodelin has highly homologous to beta-lactoglobulin, the main component of equine, bovine, and ovine milk whey (Julkunen et al., 1988) .
General function
Ligand, Growth factor
Comment
Morris et al. (1996) reported that glycodelin exists as 2 gender-specific forms that differ in their glycosylation patterns. GdA, found in amniotic fluid, inhibits sperm-zona pellucida binding in an established sperm-egg binding system; GdS, found in seminal plasma, does not. Both forms suppress responses by a variety of immune effector cell types. Izhar
Cellular localization
Secreted
Comment
Ovarian function
Comment
Effect of glycodelin on the production of vascular endothelial growth factor in cumulus cells. Hayes EC et al. Glycodelin modulates vascular endothelial growth factor (VEGF) production in cumulus cells in vitro. Patients with normal gonadotropin responses who were undergoing IVF demonstrated increased VEGF production to glycodelin, whereas poor responders had a decreased response to glycodelin.
Expression regulated by
Comment
Ovarian localization
Granulosa, Theca
Comment
Keil et al., 1999 demonstrated the expression of glycodelin mRNA in the female and male genital tracts of rats using non-radioactive in situ hybridisation. In the ovary, glycodelin mRNA was restricted to granulosa cells,
Follicle stages
Antral, Preovulatory
Comment
Tse JY, 2002 reported the synthesis and fate of glycodelin in human ovary during
folliculogenesis.
The ontogeny of glycodelin in human ovarian follicles during folliculogenesis was
studied. Glycodelin immunoreactivity began to be detected in the granulosa cells and
thecal cells of late secondary follicles. Immunoreactivity was also found in both the
luteinized granulosa cells and cumulus cells obtained from women undergoing the
assisted reproduction treatment. However, only the luteinized granulosa cells, and not
the cumulus cells, expressed glycodelin mRNA. Results also showed that the cumulus
cells took up radiolabelled glycodelin and partially deglycosylated some of it.
Glycodelin (and a partially deglycolsylated form of glycoldelin) appeared to complex
with two cytoplasmic or membrane components of the cumulus cells. The data also
demonstrated that ZIF-1, a glycoprotein isolated from human follicular fluid, was
immunologically similar to glycodelin. In conclusion, glycodelin is
synthesized in the granulosa cells of ovarian follicles at late secondary follicle stage.
It then may be released into the follicular fluid from where it is taken up and partially
modified by the cumulus cells.