Effects of superovulation on endogenous LH secretion in cattle, and consequences for embryo production.

摘要

A review. LH pulse frequency is significantly reduced by injection of equine chorionic gonadotropin or FSH preparations. This suppression appears within 8 h of treatment. Effects of superovulation on LH pulse amplitude are less consistent. The reasons for the decrease in pulse frequency have been investigated, and although the answer is not definite, it would seem that increased follicular oestradiol, acting perhaps in synergism with progesterone, may play a role. Changes in plasma progesterone concentrations are not related to changes in LH pulse frequency. Attempts have been made to understand the significance of decreased LH pulse frequency by inducing LH pulses during superovulation. Ovulation rate was markedly reduced by this intervention.