| Budget Amount *help |
¥5,000,000 (Direct Cost: ¥5,000,000)
Fiscal Year 1987: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1986: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1985: ¥3,200,000 (Direct Cost: ¥3,200,000)
|
|---|
| Research Abstract |
Mullerian inhibiting activity (MIA) in the avian embryonic gonads was assayed by a graded organ-culture method using the female Mullerian ducts (Md) of a 7-day quail embryo. Embryonic testis maintained high MIA levels during embryonic ages examined: 6 to 21 days in the chick and 5 to 17 days in the quail. The highest activity was detected between 6 and 12 days in the chick and between 7 and 11 days in the quail, corresponding to the time of normal involution of the male Md (chick: 9 to 11 days; quail: 8 to 10 days). The left ovary had moderate MIA levels during the last quarter of embryonic life, while the right ovary had little MIA throughout embryonic development in both species.
Development and loss of MIA responsiveness were determined by organ culture of the male Md and by in vitro exposing the female Md to MIA, respectively. The results suggest that Md is responsive to MIA only during the embryonic period from 8 to 9 days in the chick and from 6.5 to 9 days in the quail, respectively. This MIA responsive was modified in estrogen- treated Md.
Whether circulationg MIA levels could cause regression of Md was determined. When MIA- sensitive female Mds were grafted onto the chorioallantoic membrane (CAM) of 9-day chick and 8-day quail male embryos, respectively, Md grafts showed clear signs of reguession. When two testes from 10-day chick and 8-day quail embryos were grafted onto the CAM of 7-day chick and 6-day quail female embryos, respectively, host female Mds could be caused regression. These results suggest that circulating MIA, secreted from the embryonic testes in situ of in graft, can cause regression of either the grafted Mds or the in situ Mds at a site distant.
|
