Recombinant Equine Luteinizing Hormone Stimulates Production of Progesterone from Murine Leydig, Ovine Small Luteal, and Equine Granulosal Cells

Recombinant equine luteinizing hormone (reLH) was evaluated for its ability to stimulate production of progesterone in cell lines from three species including murine Leydig tumor (MA-10), equine granulosal, and ovine small luteal cells (SLC). The response to reLH was compared with that obtained with human chorionic gonadotropin (hCG), equine chorionic gonadotropin, ovine luteinizing hormone, and equine luteinizing hormone (eLH). Media were collected hourly for 6 hours and assayed for progesterone content through radioimmunoassay. In MA-10 cells, production of progesterone was stimulated above baseline by reLH and hCG (P < .05). Ovine SLC responded to treatment with eLH, reLH, ovine luteinizing hormone, and hCG by increasing production of progesterone above that stimulated by vehicle control (P < .05). Production of progesterone in equine granulosal cells was maximally stimulated by treatment with hCG (P < .05), followed by reLH and eLH (P < .05). In conclusion, reLH elicited a progesterone response in MA-10, ovine SLC, and equine granulosal cells. Thus, reLH stimulates the production of progesterone in cell lines from three species.