Influence of Ambient Calcium Levels on Tanniocalcin Secretion in the European EEL (Anguilla Anguilla)

1992 ◽  
Vol 162 (1) ◽  
pp. 197-208 ◽  
Author(s):  
R.G.J. M. HANSSEN ◽  
N. MAYER-GOSTAN ◽  
G. FLIK ◽  
S.E. WENDELAAR BONGA

The cells of the corpuscles of Stannius appeared to be more active in eels acclimated to sea water than in eels acclimated to fresh water. In acclimated eels, however, total and ionic plasma calcium concentrations and stanniocalcin titers did not differ. This suggests that levels of stanniocalcin in freshwater-acclimated eels are sufficient to maintain normocalcemia in sea water. When freshwateracclimated eels were transferred directly to sea water, total and ionic calcium concentrations in the plasma increased significantly within 24 h but there was no apparent effect on the corpuscles of Stannius within the same time. This suggests that changes in secretory activity of the corpuscles of Stannius do not occur rapidly when they are presented with a hypercalcemic challenge. Conversely, when seawater-acclimated eels were transferred to fresh or distilled water there appeared to be a very rapid reduction in secretory activity in the corpuscles of Stannius, as indicated by the rapid accumulation of secretory granules. These data suggest that stanniocalcin turnover is more rapid in seawater-acclimated eels and that the secretory activity of the corpuscles of Stannius is rapidly reduced when a hypercalcic challenge is removed.

1968 ◽  
Vol 42 (1) ◽  
pp. 109-117 ◽  
Author(s):  
D. K. O. CHAN ◽  
I. CHESTER JONES

SUMMARY The amounts of ionized, complexed and protein-bound calcium and total inorganic phosphate were measured in the plasma of the eel. Groups comprised freshwater, seawater and distilled water eels; treatment with corticotrophin (ACTH), cortisol, aldosterone or oestrogen; adrenalectomized and hypophysectomized eels and those with the corpuscles of Stannius removed. In the intact animal, the amounts of ultrafiltrable and ionic calcium and inorganic phosphate in the plasma were very constant despite wide variation in the electrolyte composition of the external medium. In the freshwater eel, 1 week after removal of the corpuscles of Stannius, there was a rise in the level of ultrafiltrable calcium and a decline in that of inorganic phosphate. At 3 weeks after operation, although total calcium concentration remained elevated, ultrafiltrable and ionic calcium concentrations returned to control values. Adrenalectomy and hypophysectomy of the freshwater eel resulted in a decline in total calcium concentration with change in the levels of ultrafiltrable calcium or inorganic phosphate. In the seawater eel, adrenalectomy or removal of the corpuscles of Stannius resulted in an increase in total and ultrafiltrable calcium concentrations. Injection of ACTH, cortisol or aldosterone did not affect calcium concentrations but gave a slight decline in inorganic phosphate levels. Injection of oestrogen increased total calcium concentration without affecting ultrafiltrable or ionic calcium concentrations. The relationship of the amounts of ultrafiltrable calcium and inorganic phosphate to the solubility product [ultrafiltrable calcium] × [phosphate] is discussed and attention drawn to the importance of protein-binding in calcium homeostasis.


1989 ◽  
Vol 141 (1) ◽  
pp. 177-186 ◽  
Author(s):  
R. G. Hanssen ◽  
F. P. Lafeber ◽  
G. Flik ◽  
S. E. Wendelaar Bonga

Removal of the corpuscles of Stannius (STX) in the freshwater European eel causes a marked increase in the concentrations of blood ionic calcium and protein-bound calcium. The hypercalcaemia peaks 20 days after STX and lasts at least another 20 days. In stanniectomized eels hypocalcin decreased both blood ionic and total calcium concentrations. The reduction of plasma total calcium concentration by hypocalcin is attributed to a reduction in blood ionic calcium concentration. We conclude that hypocalcin regulates blood ionic calcium levels in fish.


1976 ◽  
Vol 64 (2) ◽  
pp. 461-475
Author(s):  
N. Mayer-Gostan ◽  
T. Hirano

The IXth and the Xth cranial nerves in Anguilla anguilla were transected, and the effects upon ion and water balance were studied in fresh water and sea water, and during transfer from fresh water and vice versa. In fresh water there is a slow demineralization due to an excess loss of Na and Cl ions. During freshwater to seawater transfer the eel survives only for 4–5 days. The fish do not drink and Na efflux does not increase enough to extrude excess ions. In sea water the glossopharyngeal and vagus nerves are necessary for the maintenance of the hydromineral balance. Denervation is followed by an increase in plasma ion concentrations. Na fluxes are not modified and increased water loss is not compensated by drinking. The rapid reduction of Na efflux during transfer from sea water to fresh water is not modified by denervation.


1973 ◽  
Vol 58 (1) ◽  
pp. 105-121
Author(s):  
R. KIRSCH ◽  
N. MAYER-GOSTAN

Using isotopic procedures, the drinking rate and chloride exchanges were studied in the eel Anguilla anguilla during transfer from fresh water to sea water. 1. Following transfer to sea water there is a threefold increase of the drinking rate (lasting about 1 h). Then it falls to a minimum after 12-16 h and rises again to a maximum level about the seventh day after the transfer. Then a gradual reduction leads to a steady value which is not significantly different from the one observed in fresh water. 2. The changes with time of the plasma sodium and chloride concentrations are given. Their kinetics are not completely alike. 3. The chloride outflux increases 40-fold on transfer of the eel to sea water, but even so it is very low. After the sixth hour in sea water there is a progressive increase in the flux, so that on the fourth day it is higher (500 µ-equiv. h-1.100 g-1) than in the seawater-adapted animals (230 µ-equiv.h-1.100 g-1). 4. Drinking rate values in adapted animals are discussed in relation to the external medium. The kinetics of the drinking rate together with variations in body weights after freshwater-seawater transfer are discussed in relation to the possible stimulus of the drinking reflex. 5. Chloride fluxes (outflux, net flux, digestive entry) are compared and lead one to assume that in seawater-adapted fish one-third of the chloride influx enters via the gut and two-thirds via the gills.


1969 ◽  
Vol 43 (1) ◽  
pp. 9-19 ◽  
Author(s):  
I. CHESTER JONES ◽  
D. K. O. CHAN ◽  
J. C. RANKIN

SUMMARY A method for the study of renal function and measurement of mean ventral and dorsal aortic blood pressure for the freshwater and seawater-adapted eel, and during transfer of the animal from fresh water to sea-water, is described. Freshwater eels have higher resting blood pressure, p-aminohippuric acid (PAH) and inulin clearance rates and urine flow than seawater eels. Urine from freshwater animals has low Na, K, Ca, Mg and Cl concentrations, while the clearance rate of inorganic phosphate exceeded that of inulin. Urine from seawater animals has high Na, Ca, Mg and Cl concentrations while that of inorganic phosphate was low. Clearance rates for Ca and Mg greatly exceeded those of inulin. During transfer from fresh water to sea-water there was an initial fluctuation in blood pressure, urine flow and PAH and inulin clearance rates which lasted about 2 hr. Thereafter these gradually declined to values observed for the seawater-adapted animal. The significance of PAH and inulin clearance rates in the study of renal function in the eel and in teleosts in general is discussed.


1965 ◽  
Vol 33 (2) ◽  
pp. 319-320 ◽  
Author(s):  
I. CHESTER JONES ◽  
D. K. O. CHAN ◽  
I. W. HENDERSON ◽  
W. MOSLEY ◽  
T. SANDOR ◽  
...  

1974 ◽  
Vol 60 (2) ◽  
pp. 535-546 ◽  
Author(s):  
ERIK SKADHAUGE

1. An in vivo perfusion of the intestine of the yellow European eel (Anguilla anguilla) was used to measure the net absorption of NaCl and water, the osmotic permeability coefficient, the solute-linked water flow, and the osmolality difference against which the intestine could transport water as functions of the salinity of the surrounding water. The eels were adapted to fresh water, to sea water, and to 1½ strength sea water. 2. The osmolality difference against which the intestine could transport water was observed to be linearly related to the net transmural flow of NaCl; the solute-linked water flow had a constant hypertonicity in spite of differing net flows of NaCl. The findings are in agreement with the hypothesis of uphill water movement being caused by local osmosis due to the salt flow and with a shunt leak proportional to the transmural osmotic difference. 3. An important part of adaptation to waters of higher salinity is a pronounced increase in the intestinal absorption of NaCl. 4. The osmotic permeability coefficient varied from experiment to experiment without relation to the state of adaptation. An explanation for this finding may be that the osmotic permeability of the intestinal epithelium is of little importance for the total intestinal transfer of water.


1967 ◽  
Vol 37 (3) ◽  
pp. 297-317 ◽  
Author(s):  
D. K. O. CHAN ◽  
I. CHESTER JONES ◽  
I. W. HENDERSON ◽  
J. C. RANKIN

SUMMARY The distribution of water, electrolyte composition (Na, K, Ca, Mg, PO4, Cl) and extracellular fluid volume of eels (Anguilla anguilla L.) were investigated under different experimental conditions. Adrenalectomy of the freshwater eel was followed by an increase in body weight, a fall in the amount and concentration of sodium in serum and muscle and a shift of water into the cells. The concentration of serum potassium remained within the normal range. Adrenalectomy of the sea-water eel was followed by a decrease in body weight and an increase in the concentration of extra- and intracellular sodium. The concentration of serum calcium also increased, that of potassium remained within the normal range but the actual content diminished. Removal of the corpuscles of Stannius from the freshwater eel gave some effects similar to adrenalectomy. There was, however, no significant increase in body weight but the concentrations of serum potassium and calcium rose. Removal of the corpuscles from the sea-water eel brought about changes similar to, but less pronounced than those after adrenalectomy. The results of the injection of mammalian corticotrophin, cortisol, aldosterone and anti-aldosterone compounds are given. They are discussed in the light of the possible roles of the adrenal cortex and the corpuscles of Stannius in the maintenance of homeostasis of the eel in different environments.


1966 ◽  
Vol 34 (3) ◽  
pp. 393-408 ◽  
Author(s):  
I. CHESTER JONES ◽  
I. W. HENDERSON ◽  
D. K. O. CHAN ◽  
J. C. RANKIN ◽  
W. MOSLEY ◽  
...  

SUMMARY Extracts of corpuscles of Stannius from the silver eel have been shown to contain a substance with a powerful pressor action on intravenous injection into the rat. This material resembles mammalian renin in being non-diffusible through cellophane, heat-labile, and destroyed by acidification to pH 2. The effect in the rat differs, however, from that produced by mammalian renin in being more prolonged, and frequently biphasic. Pressor activity has also been demonstrated in extracts of kidneys from freshwater silver eels. Incubation of kidney extract with mammalian renin-substrate produced an angiotensin-like pressor substance. Both renal and corpuscular extracts had a prolonged pressor effect on intravenous injection into the eel. The identities of these pressor materials have not been finally established. Removal of the corpuscles of Stannius from freshwater silver eels was followed by a drop in blood pressure to levels normally found in eels adapted to seawater. The possible existence, in the eel, of a renin-angiotensin system analogous to that existing in mammals is discussed.


Sign in / Sign up

Export Citation Format

Share Document