COULD HORMONE-INDUCED LOSS OF GONADOTROPIN RECEPTORS REDUCE THE EFFICIENCY OF SUPER-OVULATIONS STIMULATED BY PMSG

Any future, large-scale, commercial application of embryo transfer techniques will require a continuous and reliable supply of embryos. The simplest potential method of meeting such a demand would be by superovulation using PMSG - provided treatments could be developed which are reliable and feasible in terms of cost and complexity. At present the exact requirements to modify ovulation rate in the cow are unknown. Neither are all the biological effects of treatment with PMSG understood. In an attempt to begin to clarify these areas, the literature on the biological effects of gonadotrophins, and the role of gonadotrophins in follicular development and ovulation is reviewed. In light of the very long half-life of PMSG, particular attention is paid to the ability of gonadotrophins to induce receptor loss and to desensitize target cells.