Characteristics of peaks in serum concentrations of follicle-stimulating hormone and estradiol, and follicular wave dynamics during the interovulatory interval in cyclic ewes

摘要

There are three or four ovarian follicular waves in the interovulatory interval of cyclic ewes Each follicular wave is preceded by a transient peak in serum follicle-stimulating hormone (FSH) concentrations Serum concentrations of estradiol also increase concurrent with the growth of follicle(s) in each wave In the current study, we investigated the patterns of follicular wave development and characteristics of FSH and estradiol peaks in all follicular waves of the interovulatory interval and after induction of a supraphysiologic FSH peak in cyclic ewes (Ovis aris) In Experiment 1, 19 ewes underwent daily ovarian ultrasonography and blood sampling for a complete mterovulatory interval In Experiment 2, seven ewes received two administrations of ovine FSH (oFSH), 8 h apart (1 mu g/kg, sc), at the expected time of the endogenous FSH peak preceding the second follicular wave of the mterovulatory interval. In Experiment 1 the amplitude of the FSH peaks decreased (up to 50%), whereas basal serum FSH concentrations increased across the mterovulatory interval (P < 0 05) Maximum follicular diameter was greater (P < 0 05) for Wave 1 and the Ovulatory wave (6 0 +/- 0 3 and 6 1 +/- 0 2 mm, respectively) than for Waves 2 and 3 (5 3 +/- 0 1 and 5.4 +/- 0 3 mm. respectively)