Atsuhiko Hattori

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When freshly isolated rabbit marrow cells were cultured either in vitro or in diffusion chambers in vivo, the hemopoietic cells disappeared and there was a proliferation of the stromal cell population. The colonies formed in vitro were mainly fibroblastic, and this cell type predominated in confluent cultures. Staining for alkaline phosphatase activity and(More)
Osteogenesis in the teleost was morphologically observed using regenerating scales of goldfish. Histological observations indicated that osteoblasts around the regenerating scales on days 7 to 10 were greater in size and number than those at other stages. Therefore, further experiments were carried out to examine the activity of osteoblasts in the(More)
The effects of melatonin on osteoclastic and osteoblastic cells were examined using a culture system of the goldfish scale. Tartrate-resistant acid phosphatase (TRACP) and alkaline phosphatase (ALP) were used as markers of osteoclastic and osteoblastic cells, respectively. In Earle's minimum essential medium containing melatonin (10(-9) to 10(-5) m),(More)
To examine the effects of heavy metals such as cadmium and mercury on calcium homeostasis, plasma calcium and calcitonin were measured in goldfish. Cadmium induced hypocalcemia both at 4 and at 8 days. In methylmercury-treated goldfish, the plasma calcium level increased at 2 days and then decreased at 8 days. The plasma calcitonin level increased in(More)
Gonadotropin-inhibitory hormone (GnIH), a neuropeptide that inhibits gonadotropin synthesis and release, was first identified in quail hypothalamus. GnIH acts on the pituitary and GnRH neurons in the hypothalamus via GnIH receptor to inhibit gonadal development and maintenance. In addition, GnIH neurons express melatonin receptor and melatonin induces GnIH(More)
Complementary DNAs encoding two major osteoclastic markers, tartrate-resistant acid phosphatase (TRAP) and cathepsin K (Cath K) were cloned from the scales of a teleost, the goldfish. This is the first report of the full coding sequence of TRAP and Cath K molecules in fish. In the goldfish scale both TRAP and Cath K mRNAs were expressed in the multinucleate(More)
Several reports indicate that melatonin is involved in the regulation of bone metabolism. To examine the direct effect of melatonin on osteoclasts and osteoblasts, we developed an in vitro assay using fish scales that contain osteoclasts, osteoblasts, and bone matrix, all of which are similar to those found in mammalian membrane bone. Using the assay, we(More)
The effect of fugu parathyroid hormone 1 (fugu PTH1) on osteoblasts and osteoclasts in teleosts was examined with an assay system using teleost scale and the following markers: alkaline phosphatase (ALP) for osteoblasts and tartrate-resistant acid phosphatase (TRAP) for osteoclasts. Synthetic fugu PTH1 (1-34) (100pg/ml-10ng/ml) significantly increased ALP(More)
In teleosts, it is well known that plasma calcium levels increase as a result of treatment with estrogen for at least during 2 weeks and that calcitonin secretion is induced by estrogen. The present study examined the influence of bisphenol A on calcium homeostasis in goldfish and compared the above known estrogenic action. In goldfish kept in water(More)
Using our original in vitro assay system with goldfish scales, we examined the direct effect of prostaglandin E₂ (PGE₂) on osteoclasts and osteoblasts in teleosts. In this assay system, we measured the activity of alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) as respective indicators of each activity in osteoblasts and(More)