Anuran amphibia which are not acclimable to high salt,tolerate high plasma urea

• 1.1. The capacity of five anuran Amphibians (Bufo viridis B. regularis, Rana ridibunda, Hyla arborea and Pelobates syriacus) to acclimate to NaCl and urea solutions was investigated.
• 2.2. All species could be acclimated to relatively high concentrations of urea solutions, while only Bufo viridis and Hyla arborea could be acclimated to 500 mOsm/kg or higher NaCl solutions.
• 3.3. The plasma urea concentration in B. viridis and H. arborea was elevated to levels over 140 mmol/1.
• 4.4. The sum of plasma sodium and chloride concentrations did not increase over 400 mmol/l in any species.
• 5.5. Urine osmolality, which was normally low, increased, but never exceeded the plasma osmolality.
• 6.6. In the urea acclimation conditions, urine electrolytes diminished, similarly in all species in this study.
• 7.7. It is concluded that anuran Amphibians can tolerate high plasma urea concentrations, but only those species which can elevate it, either through retention or net synthesis, can be acclimated to high salt solutions.

     

Renal response to hypoxia in carp,Cyprinus carpio: Changes in glomerular filtration rate,urine and blood properties and plasma catecholamines of carp exposed to hypoxic conditions

• 1.1. Changes in glomerular nitration rate (GFR), urine and blood properties and plasma catecholamines of carp were investigated during and following hypoxia.
• 2.2. GFR and urine flow decreased with increased urinary concentrations of bio-components, except protein, in the course of hypoxia.
• 3.3. Decreases in blood pH, and increases in haematocrit value and plasma K⁺, Ca²⁺, Mg²⁺, inorganic phosphate (P_i), ammonia, lactic acid and catecholamines (CAs) were observed as hypoxia progressed.
• 4.4. Increased GFR and urine flow, and higher values for urinary components, except protein, compared with those of the control were found in the initial post-stress stage.
• 5.5. The possible significance of increased plasma CAs in relation to changes in renal function in hypoxic carp is discussed.

     

Epidermal growth factor alters the electrolyte profile of lactating ewes Ovis aries

• 1.1. Lactating ewes were treated with mouse epidermal growth factor (EGF) at a dose rate of 0.5 mg/day for 4 days and its effects on the electrolyte profile were observed.
• 2.2. There was no effect of EGF on plasma concentrations of sodium or potassium, although urinary and total (in urine and milk) losses of both were reduced.
• 3.3. EGF-induced hypocalcaemia was associated with reduced milk calcium secretion and increased urinary calcium excretion whereas EGF-induced hypermagnesaemia was associated with reduced urinary and total magnesium losses.
• 4.4. Glomerular filtration rate was reduced during EGF infusion.
• 5.5. Chronic intravenous EGF infusion affects the electrolyte profile by altering electrolyte secretion by the mammary gland and renal electrolyte excretion.

     

The effect of reduced salinity on tissue and plasma composition of the dogfish,Squalus acanthias

• 1.1. Dogfish (Squalus acanthias) were acclimated to reduced salinities and their plasma, muscle tissue and erythrocytes subsequently analysed.
• 2.2. Decrease in the osmolarity of the plasma was principally due to a fall in urea concentration and a significant fall in the concentrations of sodium and chloride.
• 3.3. Changes in the muscle and erythrocytes in dilute media were a decrease in urea, potassium, sodium and chloride concentrations.
• 4.4. The concentrations of the free amino acids in the muscle and the red blood cells decreased more than would be expected by the movements of water only.
• 5.5. The results were discussed in relation to the regulation of cellular volume and the involvement of the free amino acid pool of the tissues in this process.

     

Urine composition and kidney function in the pulmonate freshwater snail Lymnaea stagnalis

• 1.1. Final urine is intermittently released from the pneumostome of the pulmonate freshwater snail Lymnaea slagnalis. A technique is described to sample this fluid.
• 2.2. The ionic composition of final urine greatly differs from that of haemolymph; Na⁺ and Cl⁻ are reabsorbed to a considerable degree. In lettuce fed snails K⁺ is excreted.
• 3.3. The urine Na⁺ and Cl⁻ concentrations are about 38 and 31 mM lower, respectively, than the haemolymph concentrations, also when the latter concentrations vary.

     

Ionic regulation and salinity related changes in haemolymph protein in the semi-terrestrial beachflea Orchestia gammarellus (Pallas) (Crustacea: Amphipoda)

• 1.1. Orchestia gammarellus maintained in air and provided with food in the form of agar was found to be very tolerant of changes in the ionic content of the food and was shown to have well-developed powers of ionic regulation over the salinity range 5–40‰ at 10°C.
• 2.2. There was an inverse relationship between haemolymph protein and acclimation salinity.
• 3.3. The concentration of sodium and protein ions in the haemolymph of O. gammarellus from above high water mark (H.W.M.) was markedly different from animals collected below H.W.M. Individuals taken from above H.W.M. characteristically had low haemolymph sodium but elevated haemolymph protein concentrations.

     

Salinity tolerance of adult and juvenile red king crabs Paralithodes camtschatica

• 1.1. Juvenile king crabs were more tolerant of reduced salinities than adult crab; juvenile crab were better volume regulators at reduced salinities than adult crab.
• 2.2. Adult female king crab hemolymph was hyperosmotic to full seawater (30 ppt) and isosmotic to dilute seawater. Juvenile king crab (2 years old) were hypoosmotic at the same concentrations.
• 3.3. Lower osmotic concentration of juvenile hemolymph is at least partially due to lower sodium concentration.
• 4.4. Juvenile king crab can tolerate some dilution and survive for short periods in the reduced salinity of the lower intertidal zone.

     

The effect of feed restriction on certain haematological indices,enzymes and metabolites in Nubian goats

• 1.1. Some effects of restricting feed intake for 96 or 168 hr were determined in male Nubian goats.
• 2.2. Goats restricted for 96 hr lost 11.6% of their body weight, and goats restricted for 168 hr lost 19.8%.
• 3.3. Feed restriction for up to 168 hr did not produce significant effects on the heart rate, respiratory rate or rectal temperature.
• 4.4. Haemoglobin concentration, packed cell volume and erythrocyte number were all decreased by feed restriction. There was also a tendency towards eosinopenia and lymphopenia.
• 5.5. Feed restriction for 96 or 168 hr raised the plasma activity of aspartate transaminase, and did not affect significantly cholinesterase activity. Plasma amine oxidase activity was significantly reduced in goats restricted for 168 hr.
• 6.6. Feed restriction produced significant increases in the blood or plasma concentrations of lactate. pyruvate, non-esterified fatty acids, cholesterol, ketone bodies and bilirubin.
• 7.7. Significant decreases were found in the concentrations of total protein and calcium.
• 8.8. No significant changes were observed in the plasma concentrations of glucose, sodium or potassium.

     

Effects of water stress on hemolymph volume,osmotic potential and chemical composition in Megetra cancellata

• 1.1. Rates of water loss in Megetra cancellata were very high compared to those reported for other xeric arthropods.
• 2.2. Hemolymph weight in hydrated animals was 43.0% of the total body weight while it was 24.7% in desiccated animals that had lost 16.1% of their body weight as water.
• 3.3. Hemolymph osmotic potential increased from 417 to 447 mOsm/kg in desiccated beetles, but osmotic regulation was evident.
• 4.4. Total hemolymph protein mass and concentration decreased in desiccated beetles while amino acid concentrations remained constant (at about 70 mM).
• 5.5. Na⁺ and −PO₄ concentrations increased in desiccated beetles.
• 6.6. Cl⁻ and K⁺ concentrations in desiccated beetles were equal to those in undesiccated beetles.

     

Examination of water balance and ionic regulation in the earthworm,Eisenia foetida

• 1.1. Weight change after submerging the earthworm into water varied remarkably according to the environmental humidity in which animals were placed before submergence.
• 2.2. Pretreatment with physiological saline solution before submergence in water gave stable values for the ionic concentrations of the body fluid.
• 3.3. Brain removal caused decrease of both sodium and chloride ion concentrations and increase of potassium ion concentration of the coelomic fluid when animals were submerged in water.
• 4.4. Although brain replacement failed, action of a brain hormone is suggested to regulate the decrease of both sodium and choride ions and increase of potassium ion of the coelomic fluid to normal level when animals were submerged in water.

     

Osmotic changes in an estuarine bivalve,Modiolus fluviatilis

• 1.1.Responses to different salinities monitored by opening and closing of the shell valves were observed in Modiolus fluviatilis.
• 2.2.The osmotic pressure, sodium and chloride ion concentrations were measured in the haemocoelic fluid of Modiolus fluviatilis under similar conditions.
• 3.3.Free amino acids (measured as ninhydrin-positive substances) were determined in the muscle tissue of Modiolus.
• 4.4.It appears that these free amino acids are involved in the ability of the estuarine bivalve Modiolus fluviatilis to osmoregulate in a wide range of salinities.

     

Evolution of invertebrate homeostasis: Osmotic and ionic regulation

• 1.1. Homeostasis, or the maintenance of a constant internal environment, in invertebrate organisms decreases the dependence of these organisms on the vagaries of the external environment.
• 2.2. The evolution of physiological processes influencing homeostatic conditions begins with the organism being totally dependent upon the external environment, passing through a series of intermediate stages during which fluctuation in a given internal parameter occur, proceeding finally to a condition where the internal environment is constant and independent of the external environment.
• 3.3. A hypothetical scheme for the possible evolutionary pathway of osmotic and ionic regulation in aquatic invertebrates was developed in an attempt to follow the process of homeostasis in these organisms.
• 4.4. Primitive marine cells developed mechanisms to regulate the ionic composition of the cytoplasm probably in association with the need for volume regulation.
• 5.5. The development of a body wall separated an internal body fluid from the external sea-water and the ionic composition of the body fluids was initially maintained slightly different from that of the sea-water by essentially passive means.
• 6.6. The addition of excretory organs, which arose initially through an inpushing of the body wall, brought about the ability for osmoregulation.
• 7.7. Homeostatic mechanisms must be in place before an organism can move from one environment to another.

     

A comparison of the effect of alternating current electronarcosis,rectified current electronarcosis and chemical anaesthesia on the blood physiology of the freshwater bream Oreochromis mossambicus (peters)—III. The effect on the plasma electrolytes Ca2+, Na+ and K+ and on the osmotic pressure of the blood

• 1.1. The effects of alternating current electronarcosis, rectified current electronarcosis and chemical anaesthesia (benzocaine hydrochloride) on plasma electrolytes and on the osmotic pressure of the blood of the freshwater bream Oreochromis mossambicus were evaluated.
• 2.2. Plasma Ca²⁺, Na⁺ and K⁺ concentrations and the osmotic pressure of the blood were monitored over a period of 7 days.
• 3.3. The results showed that the different electrolytes respond differently to the different techniques.
• 4.4. Chemical anaesthesia exhibited the least effects on the parameters studied.

     

Serum and urine biochemical indicators of nutritional status in adult female collared peccaries,Tayassu tajacu (tayassuidae)

• 1.1. Physiological responses of 13 adult female collared peccaries (Tayassu tajacu) to high quality and low quality diets, fed for 15 weeks, were examined. The low quality diet simulated energy and protein intake of peccaries during poor range conditions resulting from drought. Blood samples were collected after 10 and 15 weeks of dietary treatment; urine samples were collected after 15 weeks of treatment.
• 2.2. Females receiving the low quality diet for 15 weeks lost 27.4% of their original body weight, compared to no weight change among high quality-fed females.
• 3.3. Red blood cell counts, hematocrits, and hemoglobin concentrations were significantly greater among females fed a high quality diet compared to those receiving a low quality diet. High quality-fed females also had a higher mean corpuscular hemoglobin concentration. Plasma fibrinogen concentration was nearly twice as great among females receiving the low quality diet compared to the high quality group.
• 4.4. Consumption of the low quality diet resulted in significantly elevated serum levels of nonesterified fatty acids, alkaline phosphatase, phosphorus, alpha-2 globulin and alpha globulin: beta globulin ratio.
• 5.5. Consumption of the low quality diet resulted in significantly lowered serum levels of urea nitrogen, calcium, zinc, calcium: phosphorus, urea index, beta-1 flobulin, beta globulin: albumin ratio, thyroxine and triiodothyronine.
• 6.6. Serum levels ofcreatinine, total bilirubin, glucose, cholesterol, gamma glutamyltransferase, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, potassium, copper, magnesium, sodium chloride, total protein and gamma globulin were unaffected by diet quality.
• 7.7. Urine chemistry results suggested pH, osmolarity, albumin, creatinine phosphokinase, calcium and phosphorus concentrations might be useful indices for assessing nutritional status in female peccaries.

     

Lipid and carbohydrate metabolism of the intertidal crab Chasmagnathus granulata dana, 1851 (Crustacea: Decapoda) during emersion

• 1.1. Lipid, glucose and glycogen concentrations were measured in different tissues of the crab Chasmagnathus granulata during emersion.
• 2.2. After 6 hr of emersion no reduction in the total amount of carbohydrates was found to occur, suggesting that a general metabolic arrest was taking place.
• 3.3. A transitory increase in haemolymphatic glucose and lipid levels was observed. Possible causes are therefore discussed in relation to changes in the flux of substrates for energy production.
• 4.4. The mobilization of carbohydrates and lipids to the gills, observed only during summer, may be concerned with energy supplying for ionic regulation.

     

Sea water drinking as a homeostatic response to dehydration in hatchling loggerhead turtles Caretta caretta

• 1.1. Hatching Caretta caretta may lose up to 12% of their initial hatched weight from water loss during emergence from the nest.
• 2.2. After subsequent osmotic and excretory water loss in sea water, hatchlings will drink sea water (166 μl 100 g⁻¹ hr⁻¹) and return to their initial weight within 10–15 days, without feeding.
• 3.3. There were no significant changes in plasma osmolarity or sodium levels over this period.
• 4.4. This osmoregulatory strategy is in marked contrast to that seen in the estuarine crocodile, Crocodylus porosus.

     

Haematological changes in male and female pharaoh quails (coturnix coturnix pharaoh) after ekatin intoxication

• 1.1. The purpose of this study was to determine changes in the blood of pharaoh quails after Ekatin intoxication, to define the duration of disturbances caused by intoxication and to examine possible sex differences in the birds' reaction to intoxication.
• 2.2. It was found that Ekatin reduced the number of erythrocytes, haemoglobin level and haematocrit value, increased erythroblast and reticulocyte numbers and increased the osmotic resistance of blood cells.
• 3.3. It was shown that this pesticide caused neutrophilic leucocytosis with lymphopaenia and eosinopaenia.
• 4.4. In males changes in the blood appeared far earlier than in females and they underwent compensation earlier, that is, 3 weeks after intoxication the majority of the haemotological parameters reached values similar to the control.

     

Facultative aestivation in a tropical freshwater turtle Chelodina rugosa

• 1.1. Chelodina rugosa dug from aestivation sites at the end of the dry season were immediately alert and well coordinated.
• 2.2. Compared with non-aestivating animals, aestivating turtles had 20% higher plasma osmotic pressure and 7% higher sodium. Coupled with a small, but significant weight gain upon return to the water, this suggested the occurrence of minor dehydration in aestivating animals.
• 3.3. Plasma lactate levels of aestivating animals were low, averaging 1.99 mmol/l, consistent with aerobic rather than anaerobic metabolism having sustained their long period under ground.
• 4.4. No evidence was seen of dramatic physiological specialization. Aestivation in this species is interpreted as a primarily behavioural adaptation, made possible by typically reptilian abilities to tolerate a wide range in plasma electrolytes and to survive long periods without feeding.

     

Effects of streptozotocin-diabetes and l-thyroxine treatment on TSH and GH,and circulating glucose and glycerol in thyroidectomized rats

• 1.1.The response to exogenous thyroxine in thyroidectomized rats made diabetic by treatment with streptozotocin was greatly impaired, as shown by their growth retardation and the lack of increase in plasma GH and pituitary GH and TSH concentrations.
• 2.2.Insulin administration partially compensated for these endocrine alterations in diabetic thyroidectomized rats. When these animals received enough exogenous thyroxine to normalize their plasma PBI and TSH levels, insulin administration did not decrease their augmented glucose and glycerol concentrations.
• 3.3.These findings show the permissive action between thyroid hormones and insulin although some effects of the former counteract those of insulin.

     

Effects of aluminium and pH on calcium fluxes,and effects of cadmium and manganese on calcium and sodium fluxes in brown trout (Salmo trutta L.)

• 1.1. Simultaneous measurement of calcium fluxes in brown trout, at low external [Ca] (20 μ mol 1⁻¹), provided evidence of active uptake of Ca from the medium.
• 2.2. At pH 4.5, calcium influx was inhibited and efflux was stimulated.
• 3.3. Cd and Mn, but not Al, at concentrations within the ranges found in acid waters experiencing fish population decline, inhibited calcium influx. Efflux was unaffected.
• 4.4. Cd and Mn stimulated sodium influx and efflux.