| Project/Area Number |
17K15491
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Environmental and hygienic pharmacy
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| Research Institution | Japan Organization of Occupational Health and Safety Japan Bioassay Research Center |
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Principal Investigator |
Takeda Tomoki 独立行政法人労働者健康安全機構 日本バイオアッセイ研究センター(試験管理部、病理検査部), その他部局等, 主任研究員 (60596831)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2019: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2017: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
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| Keywords | プロラクチン / ダイオキシン / 育児 / 世代継承 / 発育障害 / 脳下垂体 / ラット / 育児行動 / 妊娠期曝露 / 母乳 |
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| Outline of Final Research Achievements |
We have revealed that gestational dioxin exposure reduces prolactin, a pituitary hormone essential for nursing including milk production, during the lactational stage. We examined a hypothesis that its hormone reduction targets maternal childcare to disturb offspring development. Oral dioxin treatment to pregnant rats suppressed maternal nursing behavior and milk ejection during the lactational stage, as well as the body weight and short-term memory of offspring. Supplying prolactin to dioxin-exposed dams tended to restore the above defects. Further, dioxin induced transforming growth factor expression, which suppresses prolactin-producing cell proliferation, in a nursing period-specific manner. In support of this, prolactin-positive cells in nursing dams was decreased by dioxin. These results provide novel evidence that dioxin attenuates prolactin-stimulated nursing in lactating dams to impair offspring growth, and that immaturity of prolactin-producing cells can contribute to them.
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| Academic Significance and Societal Importance of the Research Achievements |
環境化学物質の妊娠期曝露による発育障害に関する基礎研究の多くは、離乳児における影響に着目されていた。従って、本研究成果は発育障害における母親の育児の寄与を明確に示した点で、毒性学的研究における新たな展開につながる知見であると考える。更に深刻なことに、TCDD 曝露母から出生した雌児や以降の世代も低 PRL 体質となり、自身が母となった際に正常な育児ができずに児の発育に悪影響が及ぶ、いわゆる育児の不良と発育障害が世代継承する危険性をも暗示する。育児放棄や虐待の世代継承は、現代社会における問題でもある。本知見は、プロラクチンを起点とする育児への影響がその一因となりうることを暗示している。
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