WCRB2014 POSTER PRESENTATIONS (1) (335 abstracts)
1Tokyo University of Agriculture and Technology, Fuchu, Japan; 2Nagoya University, Nagoya, Japan; 3National Institute of Agrobiological Sciences, Tsukuba, Japan; 4Takeda Pharmaceutical Company, Fujisawa, Japan.
The aim of the present study was to evaluate ovarian and hormonal responses to the administration of metastin/kisspeptin analog, TAK-683, under the endocrine environments of luteal and follicular phases in goats. At 710 days after the confirmation of ovulation by ultrasonography, six goats received a prostaglandin F2α (PGF2α) injection (Day 0) followed by 10 days of CIDR-G® treatment. PGF2α was injected again at CIDR removal. Fifty μg of TAK-683 was intravenously administered (hour 0) on Day 3 (luteal phase condition: LC) and at 12 h after CIDR removal on Day 10 (follicular phase condition: FC). Blood samples were collected daily or every other day from Day −1 to Day 10, and then collected at 10-min (hours −26), 2 h (hours 624), or 6 h (hours 2448) intervals for analysis of endocrine profiles in both trials. Ovarian ultrasonographic images were assessed daily or every other day from Day −1 until the second ovulation in three of six goats. In the LC trial, small amplitude increases in the basal level of LH were observed after TAK-683 administration during hours 06 associated with a rise in estradiol concentration, followed by a surge-like release of LH with the peak time at 12.4±0.9 h (n=5) after TAK-683 administration. In the FC trial, in contrast, a surge-like release of LH occurred immediately after TAK-683 administration with the peak time at 5.0±1.1 h (n=5) which was significantly faster than that in the LC trial (P<0.05). Ovulation was detected within 3 days after TAK-683 administration in both trials. These results suggest that TAK-683 treatment induces a surge-like release of LH under the conditions of luteal and follicular phases with different peak times.