Induced luteolysis in the primate: rapid loss of luteinizing hormone receptors

The molecular mechanisms involved in luteolysis are still unclear in theprimate. This study aimed to investigate the effect of induced luteolysison the ovarian luteinizing hormone (LH) receptor and the steroidogenicenzyme, 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in the marmosetmonkey. Luteolysis was induced in the mid-luteal phase either directly bysystemic prostaglandin F2alpha (PGF2alpha), or indirectly by LH withdrawalusing systemic gonadotrophin releasing hormone antagonist (GnRHant)treatment. The LH receptor was studied by isotopic mRNA in-situhybridization and in-situ ligand binding and 3beta-HSD expression wasstudied using isotopic mRNA in-situ hybridization and immunohistochemistry.Induced luteolysis was associated with a reduction in the expression of LHreceptor (P < 0.0001) and 3beta-HSD mRNA, closely followed by areduction in the LH receptor (P < 0.05) and 3beta-HSD proteinconcentrations within 24 h. There were no differences in the findingswhether luteolysis was induced with PGF2alpha or GnRHant. This study showsthat disparate mechanisms to induce luteolysis in the primate result in anidentical rapid loss of the LH receptor and 3beta-HSD. In conclusion,induced luteolysis leads to rapid loss of the steroidogenic pathway inluteal cells.