Effect of Unilateral Ovariectomy and Injection of Bovine Follicular Fluid on Gonadotropin Secretion and Compensatory Ovarian Hypertrophy in Prepuberal Heifers

Abstract

A study was conducted to determine whether compensatory ovarian hypertrophy occurred in prepuberal heifers, and if so, could compensatory ovarian hypertrophy be prevented by injecting charcoal-extracted bovine follicular fluid (CFF). An additional objective was to determine the effect of CFF injections on follicle stimulating hormone (FSH) and luteinizing hormone (LH) concentrations following unilateral ovariectomy (ULO). Thirty-one prepuberal Angus, Hereford, and Angus X Hereford heifers were assigned by weight and breed to the following groups: Control-saline injections (C), unilateral ovariectomy-saline injections (ULO) and unilateral ovariectomy-CFF injections (ULO-CFF). In group C, a sham operation was performed on d 0 and both ovaries were removed on d 7. In groups ULO and ULO-CFF, either the right or left ovary was removed on d 0 and the remaining ovary was removed on d 7. From d 0 to 7, each heifer received an injection (iv, 7 ml/injection) of saline or CFF every 12 h. Jugular blood samples were collected immediately before each saline injection from d 0 to 7 and analyzed for FSH and LH. Unilateral ovariectomy increased ovarian (P less than .08) and follicular fluid (P less than .05) weights compared with groups C and ULO-CFF; however, lyophilized ovarian weight was similar (P greater than .05) for all groups. Injections of CFF blocked the increase in ovarian and follicular fluid weight following ULO. The total number of visible follicles per ovary was similar for all groups; however in the ULO group there was an increase (P less than .01) in those 5 to 6 mm and greater than or equal to 9 mm.(ABSTRACT TRUNCATED AT 250 WORDS)

Circulating Concentrations of Estradiol, Luteinizing Hormone, and Follicle-Stimulating Hormone during Waves of Ovarian Follicular Development in Prepubertal Cattle1

“…This finding is in agreement with previous research in which unilateral ovariectomy of prepubertal cattle resulted in a transient increase in FSH, with concentrations peaking at 24 h after removal of the ovary [19]. With unilateral ovariectomy of prepubertal cattle, the response in gonadotropin secretion to removal of the ovary depends on whether the ovary that is removed contains the large follicles, particularly the dominant follicle, that are involved in regulation of secretion of the gonadotropins.…”

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

“…The lack of an effect on testosterone secretion is consistent with observations in rats [15]. However, data regarding the effects of follicular fluid on LH secretion are less clear, since various investigators have reported increases [21,22], decreases [28], and no changes [15][16][17]23] in LH secretory dynamics during follicular fluid treatment.…”

“…In a study using prepubertal rats, administration of porcine follicular fluid abolished the post-hemicastration rise in FSH secretion and prevented compensatory testicular hypertrophy [15]. Similar studies in heifers [16] and gilts [17] showed that hemicastration-induced increases in FSH secretion and compensatory ovarian hypertrophy were abolished by porcine follicular fluid treatment, suggesting that FSH may play a similar role in the female. In the present study, steroidfree porcine follicular fluid was administered to hemicastrated ram lambs to determine its effect on FSH secretion and subsequent compensatory gonadal responses.…”

Superovulatory Response of One Ovary Is Related to the Micro- and Macroscopic Population of Follicles in the Contralateral Ovary of the Cow

“…Saiduddin et al [11] observed an increase in the number of follicles greater than 5 mm in diameter when cattle were unilaterally ovariectomized. In another study in which prepubertal heifers were unilaterally ovariectomized, there was no difference in the total number of visible follicles 7 days later; however, there was an increase in the number of follicles 5-6 mm and Ն 9 mm in diameter [12]. Lussier et al [13] also observed an increase in the number of medium follicles (3.67-8.6 mm) in heifers that had been hemicastrated for 6 days.…”