2000 Fiscal Year Final Research Report Summary
Study on the effects of endocrine disruptors on development and differentiation of gonads and central nervous system.
| Project/Area Number |
11839004
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Institution | Tokyo University of Agriculture and Technology |
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Principal Investigator |
WATANABE Gen Faculty of Agriculture, Tokyo University of Agriculture and Technology Associate Professor, 農学部, 助教授 (90158626)
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| Project Period (FY) |
1999 – 2000
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| Keywords | endocrine disruptor / octylphenol / estrogen / LHRH / sexual differentiation / inhibin |
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| Research Abstract |
We have investigated mainly about the effects of endocrine disruptors on sexual differentiation of CNS in rats.
1) LHRH secretion during neonatal period is critical for normal development of male sexual function in hypothalamo-pituitary-gonadal axis in rats. Some of endocrine disruptors are known to have estrogenic action and be able to suppress LHRH secretion. We evaluate the effects of LHRH suppression on the fertility of male rats by injecting anti-LHRH antiserum raised in goats during neonatal of male rats.
In the results, male rats received LHRH antiserum for six days after birth showed normal sperm production in their testes. When they were challenged with estrous females, they showed little mating behavior and showed no copulation. Areas of the sexual dimorphic nucleus of preoptic area in the anti-LHRH treated males seemed smaller than those of normal males and a little larger than normal females. In conclusion, LHRH suppression during the critical period of sexual differentiation in central nervous system would result in the impotence of males at adulthood.
2) We injected s.c. an estrogenic endocrine disruptor, octylphenol, to neonatal female rats from day 0 to day 5 after birth. After growing to adult, they were ovariectomized and injected estradiol-17β to see the occurrence of gonadotropin surges. Octylphenol treated females did not show LH surge at the evening after estradiol injection. When they were challenged with mature normal male rats, both the lordosis quotient and its intensity were significantly low in octylphenol treated females.
The areas of the sexual dimorphic nucleus in the preoptic area were larger than those od normal female rats.
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