Effect of LH replacement on luteal transcriptome following CET-induced luteolysis

A large body of evidence suggests that the development and maintenance of corpus luteum (CL) in primates requires the action of LH. Earlier, using CET-induced luteolysis model, we demonstrated changes in luteal transcriptome suggesting nuclear actions of LH in the primate CL. To further demonstrate the role of LH in maintenance of primate CL, replacement studies were carried out and it was observed that administration of a single injection of rhLH was sufficient to restore the progesterone to pre-CET treatment levels and prevent the CET-induced luteolysis. To elucidate the molecular mechanisms underlying the rescue of CL function, we used LH-replacement model to study immediate early changes in gene expression at a global level (Affymetrix oligonucleotide microarray) following LH replacement in CET-treated monkeys and to evaluate if the changes in gene expression mediated by LH-withdrawal can be reversed by LH replacement. Results demonstrated up-and down-regulation of various genes following LH replacement and suggested that LH-withdrawal induced changes in gene expression are reversible at least for some genes. Keywords: CL, CET, rhLH Female monkeys receiving CET treatment on day 7 of luteal phase were administered 20 IU/kg BW of rhLH or PBS (0.5 ml) i.v. at 24 h post CET treatment and blood samples were collected before and after rhLH/PBS treatments. To study changes in gene expression associated with LH replacement following inhibition of endogenous LH secretion by CET, CL was collected at 8 h (n=2) following LH replacement from female monkeys treated previously with CET for 24 h. Monkeys receiving CET on day 7 of luteal phase and 1X PBS at 24 h following CET treatment served as control (n=2) for the present study. Corpora lutea following different treatments were cut into small quarters and snap frozen in liquid nitrogen.