Ovarian and hormonal responses to single or continuous peripheral administration of senktide, a neurokinin 3 receptor agonist, during the follicular phase in goats

Peripheral administration of SB223412, a selective neurokinin-3 receptor antagonist, suppresses pulsatile luteinizing hormone secretion by acting on the gonadotropin-releasing hormone pulse generator in estrogen-treated ovariectomized female goats

“…KNDy neuropeptides like NKB and dynorphin A, as well as their respective agonists and antagonists, have attracted considerable interest as pharmacological regulators for use in the artificial control of reproductive functions. Previous studies have demonstrated that agonists and antagonists of KNDy neuropeptide affect gonadotropin and gonadal steroid secretion in mammals, including domestic animals like cattle, goats, and sheep [ 16 , 17 , 18 , 19 , 20 , 21 , 22 ].…”

The efficacy of a newly developed neurokinin 3 receptor agonist B21-750 on luteinizing hormone secretion in cycling goats

“…LH secretion is affected by the method of senktide administration. In goats, a continuous 6-h intravenous infusion of senktide during the follicular phase stimulated an immediate increase of LH secretion, whereas a single intravenous injection was insufficient to induce any significant increase in plasma LH concentration [11]. Continuous intravenous administration of senktide is considered less practical in the field.…”

“…To evaluate the effect of B21-750 on the reproductive function of goats, in the present study, we aimed to measure the response of LH secretion to a single intravenous injection of B21-750 in association with ovarian steroid hormone during the follicular and luteal phases in goats. The dose of B21-750 used was 200 nmol/head so that the results could be compared to our previous study, which evaluated the efficacy of senktide at the same dose [11].…”

“…The results of the present study demonstrate the significant effects of B21-750 on the reproductive endocrine function of female goats. The dose of B21-750, which was the same as the amount of senktide used in a previous study [11], stimulated LH secretion during the follicular phase of goats. In addition, the present study also demonstrated that LH and progesterone secretion respond immediately to B21-750 during the luteal phase.…”

“…In the FP group, it is unlikely that B21-750 treatment influenced the timing of ovulation, which occurred 3–4 days after injection, because ovulation generally occurs 3 to 4 days after the removal of CIDR inserts in the estrus-synchronized protocol of ruminants, including goats. However, the continuous intravenous infusion of senktide during the follicular phase can stimulate ovulation within 2 days after treatment [11]. The ability of senktide to induce early ovulation results from sustained increases in LH secretion, which accelerates follicular maturation.…”