Concentration of gonadotrophins in the plasma of sheep given gonadal steroid antisera to raise ovulation rate

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Abstract
The concentration of FSH and LH [luteinizing hormone] in peripheral plasma was studied in sheep from 8 h before to 17.5 h after injection (i.v.) with antisera to the steroids androstenedione, estradiol, estrone and testosterone. The fitted mean concentration of LH increases after all treatments and the increase was associated with a higher frequency of LH pulses. The greater concentration was evident for all groups by the period 3.5-6.5 h after injection, but by the end of the sampling period the concentration had returned to or towards the values in the controls. For FSH, significnt change was limited to those animals given anti-estrogen sera but it was more rapid than for LH, both groups receiving anti-estrogen sera showing an increase during the period 0.5-3.0 h after injection. The ovulation rate was increased by treatment and an effect close to 0.75 corpora lutea per ewe was maintained by treatment in subsequent estrous cycles. This declined to 0.25 corpora lutea after 2 estrous cycles without treatment.