著者

筒井 和義 南方 宏之 浮穴 和義 田中 滋康

出版者

早稲田大学

雑誌

基盤研究(S)

巻号頁・発行日

2006

---

我々は新規脳ホルモンである生殖腺刺激ホルモン放出抑制ホルモン(gonadotropin-inhibitory hormone;GnIH)を鳥類から発見した。本研究では、GnIHはヒトなどの霊長類から無顎類に至る全ての脊椎動物に存在することを明らかにした。さらに、GnIHは生殖腺刺激ホルモンの合成と放出を抑制して生殖腺の発達と機能を抑える働きがあることを明らかにした。本研究により、この新規脳分子による新しい生殖制御機構の大略が解明された。

著者

長井 孝紀 田中 滋康 高田 真理

出版者

日本膜学会

雑誌

膜 (ISSN:03851036)

巻号頁・発行日

vol.29, no.3, pp.154-160, 2004-05-01 (Released:2011-03-04)

参考文献数

20

---

Amphibians regulate the osmotic and ionic composition of their body fluids by water and ion transport across their skin. When dehydrated, desert toads press down the pelvic region of ventral skin on moist surfaces to achieve maximal water absorption. Aquaporins (AQP) are trans-membrane proteins permeable to water. We cloned three isoforms of AQP (AQP-h1, -h2, -h3) in tissues of tree frogs. AQP-h3 was abundantly expressed in the pelvic region of ventral skin, facilitating water absorption across the skin. Antibodies to AQP-h3 labeled the cell membrane of the granulosum cells in the skin. AQP-h3 was progressively expressed during metamorphosis of larval frogs. Expression of AQP-h3 was facilitated by and diuretic hormone, argine vasotocin. Collectively, AQP-h3 is a molecule to play a positive role in water absorption across the amphibian skin. In bullfrogs short circuit current across the skin was suppressed by amiloride, a blocker for epithelial Na+ channel (ENaC), showing that transport of sodium ions occurs through ENaC. Na+ transport increased in parallel with metamorphosis of the tadpole. In cultured skins of the tadpole Na+ transport was facilitated by aldosterone, but counteracted by prolactin. Such counteraction seemed to be removed by thyroid hormone (T3) during metamorphosis to adapt a terrestrial environment.