The regulation of haemolymph calcium concentration of the crab Carcinus maenas (L.)

1976 ◽  
Vol 64 (1) ◽  
pp. 149-157
Author(s):  
P. Greenaway
Keyword(s):  
Body Weight ◽  
Calcium Concentration ◽  
Calcium Uptake ◽  
Sea Water ◽  
Calcium Influx ◽  
Carcinus Maenas ◽  
Ionic Form ◽  
Calcium Balance ◽  
Active Calcium ◽  
The Difference

After acclimation, Carcinus can maintain calcium balance in dilute (35–100%) but not in low calcium sea water. 71% of total haemolymph calcium (9–54 +/− 0–42 mM) was in ionic form as compared with 90–9%(9–9mM) in sea water. On acclimation to dilute sea water the calcium activity of the haemolymph was greater than that of the medium, the difference being maintained by active calcium uptake. Carcinus is highly permeable to Ca2+, influx from sea water being 0–513 +/− 0–07 mumoles g-1 h-1 and the time constant for calcium influx 4-3 +/− 0–48 h. Calcium space represented ca. 25% wet body weight independent of body size or salinity of acclimation medium.

The Regulation of Calcium and Magnesium in the Brackish Water Polychaete Nereis Diversicolor O.F.M

1970 ◽  
Vol 53 (2) ◽  
pp. 425-443
Author(s):  
C. R. FLETCHER
Keyword(s):  
Brackish Water ◽  
Calcium Concentration ◽  
Sea Water ◽  
Calcium Influx ◽  
Coelomic Fluid ◽  
Nereis Diversicolor ◽  
Active Uptake ◽  
Calcium And Magnesium ◽  
Electrochemical Potentials

1. Nereis diversicolor tolerates changes in the concentration of calcium and magnesium in its coelomic fluid proportional to the concentrations in the medium between chlorosities of 100-1000 mM/kg of water. 2. In lower salinities both ions are maintained relatively constant providing that the ratios of these ions to chloride in the medium are similar to the ratios in sea water. 3. The ratio of the concentration of calcium in the coelomic fluid to the concentration in the medium is a function of the salinity of the medium but not of the calcium concentration. 4. Both calcium and magnesium are at lower electrochemical potentials in the coelomic fluid than in the medium, indicating that it is not necessary to invoke active uptake. 5. The rate of calcium influx is substantial. 6. In salinities below to mM of chloride/kg of water the urine must contain less calcium than the coelomic fluid. 7. The significance of these results is discussed.

Urinary Bladder Volume and the Reabsorption of Water from the Urine of Crabs

1974 ◽  
Vol 60 (1) ◽  
pp. 167-181
Author(s):  
J. A. RIEGEL ◽  
A. P. M. LOCKWOOD ◽  
J. R. W. NORFOLK ◽  
N. C. BULLEID ◽  
P. A. TAYLOR
Keyword(s):  
Body Weight ◽  
Urinary Bladder ◽  
Blood Volume ◽  
Ethacrynic Acid ◽  
Sea Water ◽  
Carcinus Maenas ◽  
Bladder Volume ◽  
Active Secretion ◽  
51Cr Edta

1. Measurements have been made to determine the blood volume, bladder volume, clearance of 131I-sodium diatrizoate and U/H for diatrizoate in the crabs Carcinus maenas and Macropipus (Portunus) depurator. 2. Observed values of clearance blood volume and bladder volume in the two species at 18 °C were: Clearance (as % blood volume per day), Macropipus 56.1±14.5; Carcinus 27.1±5.8; Blood volume (as % body weight), Macropipus 21.0±4.0; Carcinus 19.2±3.0; Bladder volume (as % blood volume), Macropipus 12.1 ±5.0; Carcinus 11.0±8.0. 3. It is shown that the measured U/H differs from that to be expected if no reabsorption of water or secretion of diatrizoate occurs. 4. 14C-inulin and 51Cr-EDTA are excreted in an essentially similar manner to 131I-diatrizoate by Carcinus, implying that any active secretion of diatrizoate must be small in magnitude. 5. Injections of ethacrynic acid decrease the U/H ratio for diatrizoate relative to that in control Carcinus injected with sea water. In some Carcinus the concentration of diatrizoate in the urine comes to exceed that initially present in the blood. Both these points are taken, with 3, as support for the conclusion that water can be withdrawn from the primary urine of Carcinus.

The Physiology of the Antennal Gland of Carcinus Maenas (L.)

1969 ◽  
Vol 51 (1) ◽  
pp. 11-16
Author(s):  
R. BINNS
Keyword(s):  
Body Weight ◽  
Sea Water ◽  
Carcinus Maenas ◽  
Urine Flow ◽  
The Body ◽  
Antennal Gland ◽  
Urine Production ◽  
The Mean ◽  
Gland Function ◽  
Water Clearance

1. The space measured by inulin distribution, the ‘inulin volume’, has been determined, and represents approximately 20% of the body weight in crabs ranging in size from 20.0 to 57.2 g. 2. After the injection of labelled inulin into crabs, the increase in activity of the medium is equal to the fall in blood inulin in all dilutions of sea water. Clearance of inulin from the blood is due only to urine production, and therefore the molecule can be used for quantitative investigations of antennal gland function. 3. Urine production in various concentrations of sea water has been determined by measuring the clearance of inulin from the blood and the rates at which the tracer appeared in the external media. By these methods the mean rate of urine production in 100% sea water was estimated to be 4.4% body weight per day. In dilute sea water the rate of urine production increases; for example, in 50% sea water the urine flow is four times greater than in normal sea water.

scholarly journals CALCIUM METABOLISM IN HELA CELLS AND THE EFFECTS OF PARATHYROID HORMONE

1968 ◽  
Vol 36 (3) ◽  
pp. 567-582 ◽  
Author(s):  
André Bernard Borle
Keyword(s):  
Parathyroid Hormone ◽  
Hela Cells ◽  
Calcium Metabolism ◽  
Calcium Concentration ◽  
Calcium Uptake ◽  
Cell Monolayer ◽  
Metabolic Inhibitors ◽  
Calcium Balance ◽  
Cell Coat ◽  
Cellular Calcium

Calcium metabolism was investigated in HeLa cells. 90% of the calcium of the cell monolayer is bound to an extracellular cell coat and can be removed by trypsin-EDTA. The calcium concentration of the naked cell, freed from its coat, is 0.47 mM. The calcium concentration of the medium does not affect the concentration of the naked cell calcium. However, the calcium of the cell coat is proportional to the calcium concentration in the medium. Calcium uptake into the cell coat increases with increasing calcium concentration of the medium, whereas uptake by the naked cell is independent of the calcium of the medium. Anaerobic conditions and metabolic inhibitors do not inhibit calcium uptake by the cell, a fact suggesting that this transfer is a passive phenomenon. The calcium in the extracellular cell coat, was not affected by parathyroid hormone. In contrast, the hormone increased the cellular calcium concentration by stimulating calcium uptake or by enhancing calcium binding to some cell components. These results suggest that, contrary to current thinking, parathyroid hormone influences the cellular calcium balance by mobilizing calcium from the extracellular fluids in order to increase its concentration in some cellular compartment. It is proposed that these effects can enhance calcium transport.

Prescription of Calcium Concentration and Pth Control

1996 ◽  
Vol 16 (1_suppl) ◽  
pp. 300-305 ◽  
Author(s):  
Eberhard Ritz ◽  
Jutta Passlick-Deetjen ◽  
Martin Zeier ◽  
Adam Stefanski
Keyword(s):  
Calcium Concentration ◽  
Calcium Uptake ◽  
Calcium Content ◽  
Phosphate Binders ◽  
Calcium Balance ◽  
Frequent Episodes ◽  
Prospective Trials ◽  
Term Maintenance ◽  
Stimulation Of

The use of calcium-containing oral phosphate binders, introduced in an effort to avoid aluminum-containing compounds, has led to more frequent episodes of hypercalcemia. This prompted the introduction of continuous ambulatory peritoneal dialysis (CAPD) solutions with diminished calcium content. The problems raised by such solutions included stimulation of parathyroid hormone (PTH) secretion and long-term maintenance of calcium balance. Some of these issues can today be answered on the basis of controlled prospective trials. Variability of the rate of intestinal calcium uptake of bone turnover, of baseline parathyroid activity, and other factors make it necessary to individualize the indication for the use of CAPD solutions with low calcium content.

Studies on Ionic Regulation in Carcinus Maenas (L.)

1961 ◽  
Vol 38 (1) ◽  
pp. 135-152
Author(s):  
J. SHAW
Keyword(s):  
Body Weight ◽  
Sea Water ◽  
Carcinus Maenas ◽  
Sodium Concentration ◽  
Sodium Balance ◽  
Uptake Mechanism ◽  
Sodium Influx ◽  
Urine Production ◽  
Sodium Loss ◽  
Total Sodium

1. The mechanism of sodium balance in Carcinus maenas has been investigated. 2. Measurements of sodium outflux showed no evidence of a decrease in surface permeability to sodium in dilute sea water. 3. The rate of urine production in normal sea water was 3.6% body weight per day and the sodium loss through the urine was insignificant compared with the total sodium loss. In 40% sea water the urine rate was increased to 30% body weight per day and the loss in the urine accounted for 20% of the total loss. 4. Measurements of sodium influx and calculation of the active component showed that the active uptake mechanism was fully saturated at all external concentrations in which the animals could survive. 5. Regulation of the blood sodium concentration is effected largely by the activation of the sodium uptake mechanism. This prevents the blood concentration falling below a critical level as long as the external concentration itself is not too low.

The Effect of Calcium on Cadmium Uptake by the Shore Crab Carcinus Maenas

1977 ◽  
Vol 67 (1) ◽  
pp. 163-173
Author(s):  
D. A. WRIGHT
Keyword(s):  
Inverse Relationship ◽  
Calcium Concentration ◽  
Sea Water ◽  
External Medium ◽  
Carcinus Maenas ◽  
Inverse Correlation ◽  
Whole Body ◽  
Shore Crab ◽  
Significant Inverse Relationship ◽  
External Calcium

The accumulation of cadmium by the shore crab Carcinus maenas (L.) is to some extent dependent upon the calcium concentration of the external medium. This effect is apparently independent of the overall salinity of the external medium and may at least partially explain previous reports of a ‘salinity effect’. Haemolymph cadmium has a highly significant inverse relationship with the external calcium concentration. This effect is less obvious with other tissues, although the whole body cadmium has a significant inverse correlation with the external calcium concentration. Both the haemolymph and gill show a significant inverse relationship between tissue cadmium and calcium. When postmoult animals were exposed to 20μ-mol l−1 Cd in 100% s.w., high concentrations of both calcium and cadmium appeared in the haemolymph. Postmoult animals in cadmium-free sea water generally had a lower haemolymph calcium concentration than intermoult animals, and the rise in haemolymph calcium seen in the presence of cadmium may indicate some degree of competition for ‘deposition sites’ between these two metals.

Oxygen Consumption of the Euryhaline Fish Aholehole (Kuhlia sandvicensis) with Reference to Salinity, Swimming, and Food Consumption

1972 ◽  
Vol 29 (1) ◽  
pp. 67-77 ◽  
Author(s):  
B. S. Muir ◽  
A. J. Niimi
Keyword(s):  
Body Weight ◽  
Oxygen Consumption ◽  
Fresh Water ◽  
Food Consumption ◽  
Sea Water ◽  
Swimming Activity ◽  
Daily Ration ◽  
Significant Difference ◽  
Fish Weight ◽  
The Difference

Active and standard metabolism of Kuhlia sandvicensis increase with fish weight to a power of about 0.8 and active is nine times standard. No significant difference was found between experiments in fresh water and 30‰ sea water at 23 C. At low swimming speeds the fish may be unable to physically take up as much oxygen as at higher speeds. Swimming activity may be essential to circulatory adequacy.Elevated oxygen consumption lasted for 42 hr following a ration of 2.3% of body weight and for 60 hr after one of 4.5%. It amounted to about 76 mg O2/g ration, equivalent to about 16% of the energy of the ration, in both cases. For a nonswimming fish the highest oxygen consumption observed following the maximum daily ration is no more than half of the difference between active and standard rates.

Calcium Regulation in the Freshwater Crayfish Austropotamobius Pallipes (Lereboullet)

1972 ◽  
Vol 57 (2) ◽  
pp. 471-487
Author(s):  
PETET GREENAWAY
Keyword(s):  
Active Transport ◽  
Calcium Concentration ◽  
Calcium Uptake ◽  
Calcium Regulation ◽  
Freshwater Crayfish ◽  
Calcium Balance ◽  
Electrochemical Gradient ◽  
Austropotamobius Pallipes ◽  
Calcium Loss ◽  
Normal Calcium

1. Calcium regulation in normal and in calcium-depleted specimens of Austropotamobius pallipes in the intermoult condition has been investigated. 2. Calcium turnover was very low and the normal calcium balance was negative for much of the winter intermoult stage. 3. Calcium uptake was against a small electrochemical gradient, at least part of the influx occurring by active transport. 4. Most of the calcium loss occurred across the gills, and the urine contribution was small. 5. Calcium-depleted animals showed only a small fall in haemolymph calcium concentration and calcium uptake was not significantly increased by depletion.

Calcium Regulation in Intermoult Gammarus Pulex

1979 ◽  
Vol 83 (1) ◽  
pp. 131-144
Author(s):  
D. A. WRIGHT
Keyword(s):  
Calcium Concentration ◽  
Regulatory Mechanism ◽  
Specific Activity ◽  
Calcium Influx ◽  
Gammarus Pulex ◽  
Whole Body ◽  
Metabolic Inhibitor ◽  
Calcium Balance ◽  
Similar Time ◽  
Total Body Calcium

The compartmentation of calcium was studied in adult intermoult Gammarus pulex. The total body calcium concentration was 547 μmol g. wet wt.−1, which is weight for weight approximately one half of the calcium concentration found in decapod crustaceans. Over 96% of whole body calcium in G. pulex was found in the exoskeleton. 45Ca exchange curves for haemolymph and hepatopancreas had similar time constants indicative of a comparatively large pool of freely exchangeable calcium. The parallel exchange of calcium between the haemolymph and other soft tissue compartments confounded the satisfactory use of analgebraic model for indirect calcium influx measurement using haemolymph specific activity. All calcium influx was subsequently measured on a whole bodybasis. Passive absorption of calcium on to the cuticle was eliminated as a significant factor as the metabolic inhibitor 2:4-DNP almost completely inhibited any form of calcium uptake. The active nature of the calcium regulatory mechanism was further illustrated by potential difference measurements indicating that calcium is accumulated against an electrochemical gradient from media having a calcium activity less than 1 mmol l−1. When placed in calcium-free media, intermoult Gammarus pulex areable to achieve at least a tenuous calcium balance between 12 and 50μmol Ca l−1 at a density of 1 animal per 10 ml medium. Some specimens showa slow calcium loss. The calcium regulatory mechanism is saturated at an external calcium concentration of 2 mmol l1, which is the normal field calcium concentration for this population, and has a half saturation valueof 0.3 mmol l−1.

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