Exposure of Atlantic salmon smolts to estrogenic compounds is shown to compromise several aspects of smolt development. We sought to determine the underlying endocrine mechanisms of estrogen impacts on the growth hormone (GH)/insulin-like growth factor I (IGF-I) axis. Smolts in freshwater (FW) were either injected 3 times over 10 days with 2 μgg(-1) 17β-estradiol (E2) or 150μgg(-1) 4-nonylpheno...

Previous studies on non-diadromous euryhaline teleosts introduced a hypothesis that the lowest level of gill Na(+)/K(+)-ATPase (NKA) activity occurs in the environments with salinity close to the primary natural habitats of the studied species. To provide more evidence of the hypothesis, two medaka species, Oryzias latipes and O. dancena, whose primary natural habitats are fresh water (FW) and ...

The sea lamprey, Petromyzon marinus, is an anadromous, semelparous species that is vulnerable to endangered in parts of its native range due in part to loss of spawning habitat because of man-made barriers. The ability of lampreys to return to the ocean or estuary and search out alternative spawning river systems would be limited by their osmoregulatory ability in seawater. A reduction in toler...

Freshwater (FW) fishes actively absorb salt from their environment to tolerate low salinities. We previously reported that vacuolar-type H(+)-ATPase/mitochondrion-rich cells (H-MRCs) on the skin epithelium of zebrafish larvae (Danio rerio) are primary sites for Na(+) uptake. In this study, in an attempt to clarify the mechanism for the Na(+) uptake, we performed a systematic analysis of gene ex...

The mechanism of active, osmoregulatory ion uptake was investigated in the pleopods of the marine isopod Idotea baltica (Pallas). Using isolated split half-podites of isopods acclimated to brackish water (20 salinity) mounted in a micro-Ussing chamber and symmetrically superfused with identical haemolymph-like salines, a mean short-circuit current I(sc) of -445 microA cm(-)(2) was measured in e...

The development of an ion regulatory mechanism for body fluid homeostasis was an important trait for vertebrates during the evolution from aquatic to terrestrial life. The homeostatic mechanism of Cl(-) in aquatic fish appears to be similar to that of terrestrial vertebrates; however, the mechanism in non-mammalian vertebrates is poorly understood. Unlike in mammals, in which the kidney plays a...

A little-known microtubule-binding protein promotes cell migration during development. Werner et al. fi nd that the protein, CLAMP, stabilizes microtubules at the front of crawling cells and enables the cells to fi t in when they reach their new home (1). Embryonic cells and cancer cells often travel far from their birthplace and may have to traverse barriers to reach their destinations. During...

The directed movement of cells is a fundamental aspect of tissue morphogenesis. Cells migrating in vivo often must invade tissue barriers and ultimately form new cellular contacts in their target tissues. Furthermore, in many epithelial tissues proliferation occurs via a population of basal stem cells that divide below the apical surface and move apically to join the epithelium (Rock and Hogan,...

THE RH BLOOD GROUP-RELATED PROTEINS have recently been recognized as ammonia transporters acting in erythrocyte and nonerythrocyte membranes. They play an important role in excretion of nitrogenous waste formed mainly from amino acid metabolism. Because of a restricted availability of water, most terrestrial animals detoxify ammonia into urea or uric acid before removal from the body. However, ...