| Project/Area Number |
09460147
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied veterinary science
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| Research Institution | Nippon Veterinary and Animal Science University |
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Principal Investigator |
TSUTSUI Toshihiko Nippon Veterinary and Animal Science University, Department of Veterinary and Animal Science, Professor, 獣医畜産学部, 教授 (40060529)
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| Co-Investigator(Kenkyū-buntansha) |
HORI Tatsuya Nippon Veterinary and Animal Science University, Department of Veterinary and Animal Science, Assistant, 獣医畜産学部, 助手 (80277665)
KAWAKAMI Eiichi Nippon Veterinary and Animal Science University, Department of Veterinary and Animal Science, Assistant Professor, 獣医畜産学部, 助教授 (80139352)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥7,700,000 (Direct Cost: ¥7,700,000)
Fiscal Year 1999: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1998: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1997: ¥3,200,000 (Direct Cost: ¥3,200,000)
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| Keywords | canine / contraception / anti-GnRH / ovary / testis / 精液 / LH / 発情 |
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| Research Abstract |
In place of permanent contraception by excision of the gonadal glands, a new immunological contraception method using GnRH for dogs was investigated. I. Twenty beagles aged 1-7 years were used in the experiment. After administration of GnRH-KLH, the time-course blood anti-GnRH antibody titer, LH level, and progesterone (P_4) level, and state of estrus were observed. After a single dose of GnRH-KLH, the time-course anti-GnRH antibody titer was kept at a low level and estrus was not inhibited. After two administrations, although there were individual differences, the anti-GnRH antibody titer obviously increased and persisted for 11 weeks on average. In dogs with a high anti-GnRH antibody titer, LH secretion was strongly inhibited. LH secretion recovered as the anti-GnRH antibody titer decreased and estrus returned. II. Twelve beagles aged 2-3 years were used in the experiment. The blood anti-GnRH antibody titer, LH level, and testosterone (T) level, and the size of the testis and semen properties were observed after administration. While the anti-GnRH antibody titer did not increase in the control dogs, the titer rapidly increased after the booster in the GnRH-KLH treatment group and secretion of LH and T was inhibited as the antibody titer increased, resulting in atrophy of the testis and a decrease in the number of sperm cells. Azoospermia developed and persisted for 4-15 weeks, 10.4±1.9 (SE) weeks on average, in five treated animals (55.6 %). This finding suggests that an increase in the dose of GnRH-KLH may maintain the anti-GnRH antibody titer at a higher level. Spermatogenesis recovered as the anti-GnRH antibody titer decreased.
To maintain the contraceptive period, a booster administration may be necessary. Contraception may be obtained in female dogs by active immunization with GnRH.
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