著者

内山 実 上条 雅 松田 恒平 吉沢 英樹

出版者

日本宇宙生物科学会

雑誌

Biological Sciences in Space (ISSN:09149201)

巻号頁・発行日

vol.14, no.1, pp.22-31, 2000 (Released:2006-02-01)

参考文献数

56

被引用文献数

1 1

---

The Amphibia bridge the phyletic gap between the aquatic fishes and the terrestrial vertebrates. This transition has involved many interesting changes of metabolisms. In this short review, we have attempted to summarize the kidney structure and functions on the osmoregulations in the Amphibia. Amphibians excrete the water absorbed through their skin as a dilute urine. Pronephros of tadpoles may start to work in the hatching stages and metanephros is well developed and functions. Glomerular filtration rate is relatively large and glomerular intermittency is important to regulate urine production. The proximal tubule reabsorbs approximately 20-45% of filtered water and sodium. Absorption is driven by the basolateral Na+, K+-ATPase common to all tubular cells. The diluting segment, early parts of distal nephron, highly develops basolateral interdigitation and reabsorbs approximately 40% of filtered Na+, K+, and Cl-, but is impermeable to water, thus this part results in the formation of hypo-osmotic tubular fluid. In the late distal tubule, the primary mechanism of reabsorption may be via a luminal NaCl synporter, driven by the ubiquitous Na+, K+-ATPase on basolateral membrane. In collecting tubule, there are two types of cells, the principal cells and the intercalated cells. Many hormonal and nervous regulations are involved in the glomerular filtration rate and reabsorptions in the amphibian nephrons.

著者

笹山 雄一 小泉 隆 小黒 千足 神戸川 明 吉沢 英樹 Magtoon Wichian

出版者

日本水産學會

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.57, no.5, pp.851-855, 1991

被引用文献数

1 1

---

In the Brockmann bodies of the Medaka <i>Oryzias latipes</i> (Teleostei) calcitonin-like immunore-activity was detected immunohistochemically. Many cells in the endocrine tissue of the Brockmann body were stained positively by anti-salmon calcitonin antiserum and anti-eel calcitonin antiserum. Administration of the Brockmann body homogenate to rats caused significant hypocalcemia and hypophosphatemia. However, the calcemic potency of a Brockmann body was rather lower than that of the ultimobranchial gland of the Medaka itself.