Relaxin stimulates glycodelin mRNA and protein concentrations in human endometrial glandular epithelial cells

Human endometrium is the major organ that produces glycodelin A (GdA), The production of endometrial GdA causes a fluctuation of the peripheral glycod elin concentrations in women during the menstrual cycle and pregnancy. It h as recently been reported that the rise of plasma concentrations of glycode lin is correlated with relaxin during the late luteal phase and early pregn ancy. In addition, administration of relaxin increases glycodelin plasma co ncentrations, suggesting that relaxin induces GdA production in endometrium . To investigate whether relaxin regulates the GdA synthesis, human endomet rial glandular epithelial cells were isolated and cultured with or without relaxin for up to 4 days. Western blot showed that GdA synthesized and secr eted from epithelial glands had a major molecular weight of 28 kDa, i.e. th e same as the GdA isolated from amniotic fluid, Cells incubated with relaxi n consistently increased in GdA production rate (2-6-fold). The GdA mRNA co ncentrations increased 2-11-fold in cells incubated with relaxin for 2-4 da ys, as determined by solution hybridization/ribonuclease protection assay. The increase of the mRNA concentration indicates that relaxin activates GdA transcription.