The effect of hypophysectomy and prolactin treatment on the osmotic water influx into the isolated gills of the Japanese eel (Anguilla japonica)

1977 ◽  
Vol 55 (5) ◽  
pp. 872-876 ◽  
Author(s):  
Mizuho Ogawa
Keyword(s):  
Fresh Water ◽  
Sea Water ◽  
Anguilla Japonica ◽  
Japanese Eel ◽  
Osmotic Permeability ◽  
Water Influx ◽  
In Vitro Technique ◽  
Osmotic Water

An in vitro technique has been used to measure the osmotic water influx into the isolated gills and the osmotic permeability of the gill surface of the Japanese eel, Anguilla japonica. Hypophysectomy increases both of these measurements. Prolactin injections decrease both osmotic water influx and osmotic permeability to water in both the intact and hypophysectomized eels in fresh water but produce no change in either of these parameters when the fish (either intact or hypophysectomized) are in sea water. The possible role of the pituitary (especially prolactin) in osmoregulation of fishes is discussed and considered in relation to the environmental calcium in sea water.

Onset and rate of drinking in rainbow trout (Salmo gairdneri) following transfer to dilute seawater

1979 ◽  
Vol 57 (10) ◽  
pp. 1863-1865 ◽  
Author(s):  
Roger M. Evans
Keyword(s):  
Rainbow Trout ◽  
Water Balance ◽  
Water Loss ◽  
Sea Water ◽  
Direct Method ◽  
Anguilla Japonica ◽  
Japanese Eel ◽  
Salmo Gairdneri ◽  
Normal Water ◽  
A Direct Method

Seawater-adapted teleosts drink to offset water loss by osmosis. A direct method of monitoring drinking by implanting a fistula to drain the stomach indicated that rainbow trout began drinking from about 9 to 12 (range 1 to 22) h after being placed in 15‰ sea water. Unlike the Japanese eel (Anguilla japonica). in which the onset of drinking has been shown to be immediate and reflex-like, the onset of drinking in trout appears to occur only after appreciable water has been lost to the medium. The trout resembles the eel in that the capacity to shallow water in the absence of postingestional negative feedback exceeds the rate of drinking required to maintain normal water balance.

Role of Erythropoietin in Megakaryocyte Colony Formation in Man

1979 ◽  
Author(s):  
W. Vainehenker ◽  
J. Breton-Gorius
Keyword(s):  
Bone Marrow ◽  
Linear Relationship ◽  
Colony Formation ◽  
Colony Stimulating Factor ◽  
Plasma Clot ◽  
In Vitro Technique ◽  
One Step ◽  
Stimulating Factor

We have recently realized megakaryocyte (MK) colony formation in culture from blood and bone marrow progenitors using the plasma clot technique. In this study, the MK stimulating factor was an erythropoietin (Epo) either a poorly purified one(step III from anaemic sheep serum, a crude serum from anaemic mice, an urinary human Epo) or a highly purified one (GOLDWASSER). Similar results were obtained with all these Epo. A linear relationship was found between the number of colonies and seeded cells. However with less than 5.105 plated cells from the blood, no MK colonies were obtained, although erythroid colonies could be grown. In contrast, without Epo, spontaneous colonies could be observed which represented 1/5 th of the maximum plating efficiency , in these eases no erythroid colonies were present. These data suggest that Epo itself acts an a MK colony stimulating factor; but is not the only factor involved in the formation of MK colonies. This in vitro technique will be useful of in determining the factors regulating megakaryocytopoiesis.

THE OSMOREGULATORY ROLE OF THE THYROID GLAND IN THE STARRY FLOUNDER, PLATICHTHYS STELLATUS

1959 ◽  
Vol 37 (6) ◽  
pp. 997-1060 ◽  
Author(s):  
Cleveland P. Hickman Jr.
Keyword(s):  
Thyroid Gland ◽  
Fresh Water ◽  
Body Fluid ◽  
Sea Water ◽  
Salt Water ◽  
Standard Metabolic Rate ◽  
Energy Demands ◽  
Platichthys Stellatus ◽  
Fluid Concentration

Energy demands for osmotic regulation and the possible osmoregulatory role of the thyroid gland were investigated in the euryhaline starry flounder, Platichthys stellatus. Using a melting-point technique, it was established that flounder could regulate body fluid concentration independently of widely divergent environmental salinities. Small flounder experienced more rapid disturbances of body fluid concentration than large flounder after abrupt salinity alterations.The standard metabolic rate of flounder adapted to fresh water was consistently and significantly less than that of marine flounder. In supernormal salinities standard metabolic rate was significantly greater than in normal sea water. These findings agree with the theory that energy demands for active electrolyte transport are greater in sea water than fresh water.Thyroid activity was studied in flounder adapted to fresh water and salt water. Percentage uptake of radioiodine by the thyroid was shown to be an insensitive and inaccurate criterion for evaluating thyroid activity in different salinities because removal rates of radioiodine from the body and blood differed between fresh water and marine flounder. Using thyroid clearance of radioiodine from the blood as a measure of activity, salt-water flounder were shown to have much greater thyroid clearance rates and, hence, more active thyroid glands than flounder adapted to fresh water. The greater activity of the thyroid of marine flounder correlates with greater oxygen demands in sea water and suggests a direct or adjunctive osmoregulatory role of the thyroid gland of fish.

The role of environmental calcium in freshwater survival of the marine teleost, Lagodon rhomboides

1976 ◽  
Vol 65 (3) ◽  
pp. 529-538
Author(s):  
J. C. Carrier ◽  
D. H. Evans
Keyword(s):  
Fresh Water ◽  
Sea Water ◽  
Chelating Agent ◽  
Marine Teleost ◽  
Lagodon Rhomboides ◽  
Na Efflux ◽  
Total Body ◽  
Na Uptake ◽  
Marine Teleost Fish

(1) The marine teleost fish, Lagodon rhomboides, can only tolerate fresh water (5 mM Na) if Ca is also present (10 mM). Transfer to Ca-free fresh water is followed by a substantial increase in radioactive Na efflux with little or no change in the transepithelial potential. Addition of the chelating agent EDTA (2 mM) further increases Na efflux. Fish left in Ca-free fresh water for 2-5 h die with a total body Na less than 50% of that found in animals acclimated to Ca-supplemented fresh water. (2) Rates of Na uptake were measured on either sea-water-acclimated or Ca-supplemented fresh water-acclimated fish transferred to various low Na media. In both cases Na uptake has a high Km, is saturable, inhibited by external NH4, H and amiloride, and is not related to changes in the trans-epithelial potential. (3) It is suggested that L. rhomboides is dependent upon external Ca to decrease diffusional Na loss in low salinities so that a relatively inefficient Na uptake can balance diffusional and urinary Na loss.

Molecular cloning of fresh water and deep-sea rod opsin genes from Japanese eel Anguilla japonica and expressional analyses during sexual maturation 1

FEBS Letters ◽  
2000 ◽  
Vol 469 (1) ◽  
pp. 39-43 ◽  
Author(s):  
Huan Zhang ◽  
Kunihiko Futami ◽  
Noriyuki Horie ◽  
Akihiro Okamura ◽  
Tomoko Utoh ◽  
...  
Keyword(s):  
Molecular Cloning ◽  
Fresh Water ◽  
Sexual Maturation ◽  
Deep Sea ◽  
Anguilla Japonica ◽  
Japanese Eel ◽  
Opsin Genes
Sign in / Sign up

Export Citation Format

Share Document