Use of bovine follicular fluid to increase ovulation rate or prevent ovulation in sheep

Abstract

Summary. Romney ewes were injected intramuscularly once or twice daily for 3 days with 0, 0\m=.\1,0\m=.\5, 1 or 5 ml of bovine follicular fluid (bFF)

Follicular Fluid Administration Delayed, but did not Prevent, the Hemicastration-Induced Increase in Follicle-Stimulating Hormone Secretion and Compensatory Testicular Hypertrophy in Ram Lambs1

“…After termination of follicular fluid treatment, FSH concentra- tions increased again, peaking at concentrations -60% greater than those observed in saline-treated HC animals. This FSH hypersecretion has been observed in other studies [20][21][22] and may reflect the release of accumulated pituitary FSH stores once the suppressive effects of follicular fluid have ceased. Interestingly, despite the delayed FSH rise and hypersecretion after cessation of treatment, the temporal patterns of FSH secretion in HC and HC+FF lambs were remarkably similar.…”

“…The basis for the inability of follicular fluid to maintain suppression of FSH secretion is not known; however, similar results have been reported in chronically treated male and female rats [23], female monkeys [24], and ewes [20,22]. One possibility is that a refractoriness to follicular fluid administration develops, perhaps as a result of altered negative feedback responses [22]. Alternatively, chronic exposure to foreign proteins in the follicular fluid may induce an immunologic response that curtails the ability of the follicular fluid to suppress FSH [24].…”

“…It also raises an interesting question: whether long-term ablatement of FSH secretion could completely prevent hemicastration-induced compensatory events or whether these events would only be delayed until termination of treatment. The basis for the inability of follicular fluid to maintain suppression of FSH secretion is not known; however, similar results have been reported in chronically treated male and female rats [23], female monkeys [24], and ewes [20,22]. One possibility is that a refractoriness to follicular fluid administration develops, perhaps as a result of altered negative feedback responses [22].…”

“…The factors responsible for the FSH-suppressing activity of follicular fluid have not been conclusively identified, although inhibin has been suggested to be a major contributor [12,20,22,23]. We [5,25] and others [1,2,4,26] have speculated that increased FSH secretion after hemicastration is the result of a reduction in gonadal release of inhibin and that this elevated FSH secretion mediates the compensatory testicular hypertrophy response.…”

Effects of oestradiol-17 , progesterone or bovine follicular fluid on the plasma concentrations of FSH and LH in ovariectomized Booroola ewes which were homozygous carriers or non-carriers of a fecundity gene

“…On the day of the experiment, hourly blood sampling began at 09:00 h for 29 h with the bFF being administered immediately after the 13:00 h blood sample, and again just after the subsequent 01:00 h blood sample. All ewes were treated with the same pooled batch of bFF (Batch V), which was prepared free of steroids as previously described (Henderson et al, 1986).…”