Running performance of the thirteen-lined ground squirrel,the eastern chipmunk and the albino Norway rat

• 1.1. The procedure used to compare the forced running performance of three rodent species was the number of electrical stimuli required each minute to keep the animals running.
• 2.2. During running trials, ground squirrels, Spermophilus tridecemlineatus, required fewer stimuli than white rats. Squirrels ran 12.4 ± 6.9 (2 SE) min before requiring stimulation vs 3.1 ± 1.4 min for rats.
• 3.3. Total oxygen consumption during the running period was significantly higher for ground squirrels than white rats, 4.70 ± 0.36 and 4.18 ± 0.38ml O₂/g/hr, respectively.
• 4.4. Heart weight/body weight ratios were significantly higher for the ground squirrels than the white rats.
• 5.5. No differences were noted between ground squirrels and chipmunks other than those which could be accounted for by body weight differences.

     

Effect of hibernation on liver and kidney metabolism in 13-lined ground squirrels

• 1.1. Metabolic rates and adenine nucleotide content of liver and kidney from hibernating ground squirrels were measured and compared to rats to study the biochemical adaptation to hibernation.
• 2.2. High rates of renal and hepatic gluconeogenesis were observed in squirrels, particularly from propionate and glycerol compared to rat.
• 3.3. During hibernation and starvation soluble phosphoenolpyruvate carboxykinase activity was increased in both liver and kidney.
• 4.4. Although metabolic rates are decreased during hibernation the results suggest that the enzymic complement is maintained at high activity even during torpor.

     

The mechanism of calcium-dependent activation of respiration of liver mitochondria from hibernating ground squirrels,Citellus undulatus

• 1.1. It is shown that Ca²⁺-dependent activation of respiration of liver mitochondria from hibernating ground squirrels is accompanied by mitochondrial swelling.
• 2.2. The swelling of mitochondria from hibernating ground squirrels, as well as the activation of mitochondrial respiration, is precluded by cyclosporin A, p-bromphenacylbromide and oligomycin. Carboxyatractiloside, on the contrary, under these conditions favors the swelling and the acceleration of respiration.
• 3.3. It was concluded that Ca²⁺-dependent activation of hibernating ground squirrel liver mitochondrial respiration resulted from the appearance of a non-specific permeability pathway and from swelling of mitochondria.

     

Evaporative water loss and uptake in juvenile and adult Salamandra salamandra (L.) (Amphibia: Urodela)

• 1.1. Both juveniles and adults of this rare salamander were studied.
• 2.2. The rate of evaporative water loss increased with temperature and at lower humidities.
• 3.3. At all four temperatures and three humidities studied, adults lost water at a lower rate than juveniles.
• 4.4. Aggregating juveniles reduced water loss especially at lower moisture.
• 5.5. The rate of water uptake was greater in juveniles than in adults.
• 6.6. Juveniles were capable of absorbing moisture from moist soil even at 40% saturated soil.

     

Effects of starvation and a carbohydrate-rich diet on glycogen metabolism in a gastropod mollusc,Megalobulimus oblongus

• 1.1. Administration of a carbohydrate-rich diet increased haemolymph glucose levels and glycogen concentration in hepatopancreas, mantle and muscle.
• 2.2. Glycogen concentration in tissues decreases after 2 weeks of starvation and haemolymph glucose levels did not change significantly.
• 3.3. However, starvation did not induce a decrease in the intrinsic synthetic capacity in tissues.
• 4.4. Glycogen synthesis in tissues from animals fed with lettuce or a carbohydrate-rich diet, increases with increasing glucose concentration in the media.
• 5.5. However, in mantle slices from snails adapted on a carbohydrate-rich diet, the glycogen synthetic capacity was lower than in slices from snails fed with lettuce.

     

Carbohydrate metabolism in several tissues of rainbow trout,Oncorhynchus mykiss,is modified during ovarian recrudescence

• 1.1. Several pathways of carbohydrate metabolism were evaluated in three different tissues—liver, gonad and kidney—of a hatchery-reared population of rainbow trout (Oncorhynchus mykiss) which characterised two different stages of their gonadal maturation, i.e. previtellogenesis and established exogenous vitellogenesis.
• 2.2. A fall in liver glycogen levels was observed during exogenous vitellogenesis. A decrease in activity of the enzymes involved in glycolysis and in the pentose phosphate shunt was also observed, suggesting that at the end of exogenous vitellogenesis the necessity of energy and reducing power has decreased compared to the situation at the onset of this period.
• 3.3. The main changes observed in gonad during vitellogenesis were the decreased activity of glycolysis and the pentose phosphate shunt as well as increased glycogen levels. The stored glycogen should be used later in association with the embryo development.
• 4.4. No major changes were observed in kidney metabolism throughout the vitellogenic process.
• 5.5. Exogenous vitellogenesis in rainbow trout is mainly associated with increased glycogen levels in the gonad and decreased metabolic activity in the liver.

     

Identification of a glycoprotein complex containing a glycogen synthase isozyme in Ascaris Suum obliquely-striated muscle

• 1.1. A glycogen/protein complex which contains the major portion of glycogen synthase activity in Ascaris suum muscle has been purified.
• 2.2. The complex contains two proteins which can be dissociated from a glycoprotein component.
• 3.3. The glycoprotein contains glycogen-like domains and is resistant to trypsin digestion.
• 4.4. The glycogen synthase activity in the purified complex catalyzes glycogen synthesis in the absence of exogenous glycogen, but demonstrates an absolute glucose 6-phosphate requirement for activity.
• 5.5. The data support the hypothesis that this isozyme of glycogen synthase is significantly different from the cyclic AMP-regulated enzyme.

     

Glycogen synthetase in the sea mussel Mytilus edulis L.—II. Seasonal changes in glycogen content and glycogen synthetase activity in the mantle tissue

• 1.1. The glycogen content of the mantle tissue reached a maximum in the summer (May–July) with levels of 41.0–53.5% of the dry tissue weight.
• 2.2. Seasonal changes in glycogen synthetase activity showed that the I-activity (independent of G6P) increased up to 10-fold in June as compared with December. The measured I-activity of glycogen synthetase was sufficient to account for the accumulation of mantle glycogen in the summer.
• 3.3. The I-activity of glycogen synthetase declined rapidly in July of each year. A possible role for the inhibition of glycogen synthetase by high levels of tissue glycogen is suggested.
• 4.4. The I-activity in the mantle tissue of mussels on the shore was higher than that for animals starved in the laboratory for 2–3 days. The differences were minimal in early May but increased markedly in late May–July. Starved mussels returned to the shore showed an increase in I-activity of glycogen synthetase.
• 5.5. Injection of 30 μmol glucose into the adductor muscle increased the concentration of glucose in the mantle fluid to 2.0–2.5 mM. A similar injection of 60 μ mol glucose resulted in a time-dependent increase in the I-activity of glycogen synthetase.
• 6.6. Injection of mussels with mammalian insulin or anti-insulin serum had no effect on the activity of glycogen synthetase. Our results are at variance with those of other workers who have used the mammalian hormone in molluscan studies (see Discussion).

     

Changes in glycolytic and associated enzyme activities during rana ridibunda oocyte development

• 1.1. Most of glycolytic and associated enzymes in the oocytes of the frog Rana ridibunda exhibit a higher activity at the early growth stages; the activity declines by the time the oocyte reaches full growth. Citrate syntase follows a similar pattern.
• 2.2. Enzymes related to gluconeogenesis have non-detectable activity.
• 3.3. It is suggested that at the early stages of oocyte growth glycogen could contribute as a fuel mainly for the pentose phosphate pathway; in the full-grown oocyte glycogen could serve mainly as a fuel for the glycolytic pathway.

     

Trehalose synthase and trehalase behaviour in yeast cells in anhydrobiosis and hydrobiosis

• 1.I. Trehalose synthase and trehalase behaviour has been analysed in cultured yeast cells isolated from baker's yeast to increase the understanding of the mechanisms involved in trehalose content modifications observed in anyhydrobiois and hydrobiosis.
• 2.2. After desiccating yeast cells to a constant weight, trehalose levels sharply increased, whereas the glycogen content decreased, trehalose synthase was stimulated and trehalase was significantly inhibited.
• 3.3. In desiccated cells after a rehydration for 15 min, trehalose levels dropped, the glycogen content further decreased, the activity of trehalose synthase declined while that of trehalase was dramatically stimulated.
• 4.4. After rehydration for 12hr, while the trehalose and glycogen content decreased even more, the behaviour of the two enzymes was completely reversed, trehalose synthase being activated and trehalase inhibited.
• 5.5. The reasons for such impressive enzyme activity alterations in desiccated and rehydrated cells for the moment remain unknown.

     

Aerobic glucose disposal in the oyster: An in vivo kinetic analysis

• 1.1. Aerobic glucose disposal in starved oysters exposed to 1 mM external glucose was 2.29 μg C/g wet wt/min.
• 2.2. It was hypothesized that the maximum disposal rate is limited by the maximum rate of transepithelial glucose transport.
• 3.3. The major recipients of glucose-carbon were glycogen and amino acids. 4. The rate of glucose-carbon disposal to these two pools was 0.80 and 0.42 μg C/g/min, respectively.
• 4.5. The internal energy state determines the pathways of glucose disposal.
• 5.6. Disposal of glucose-carbon in “glucose-primed” oysters is primarily into glycogen.
• 6.7. In fasted bivalves the disposal is primarily into amino acids and carboxylic acids.
• 7.8. The uptake of dissolved glucose has the potential of contributing significantly to growth under conditions where the external glucose concentration is kept artificially high.

     

The glycogen content in stressed marine bivalves: The initial absence of a decrease

• 1.1. Changes in the glycogen content, condition, stomach content and acetic acid concentration of mussels Mytilus edulis and cockles Cerastoderma edule were followed during periods of up to 14 days of exposure (to air) at temperatures of 5 and 20°C.
• 2.2. In animals with a high glycogen content the glycogen is not used during the first 3 to 7 days, at high and low temperature respectively.
• 3.3. After this latent period the glycogen concentration often decreased, coinciding with a high mortality and an increase of the concentration of acetic acid.
• 4.4. In cockles with a low glycogen content, and kept at a high temperature, glycogen can be used from the beginning of the stress period.
• 5.5. Between species no clear differences were found.
• 6.6. The stomach content decreased during exposure; however, the stomach content amounted to only 0.5 to 0.7% of the body weight, and is thought to be of minor importance as an energy source during the stress period.
• 7.7. Especially at the higher temperatures glycogen finally is transformed into acetic acid.
• 8.8. It is concluded that during exposure, the animals do not die because of a lack of energy reserves, but because of a high accumulation of acids.

     

Three digestive tract endocrine peptides and the circannual cycle of body weight in Spermophilus lateralis

• 1.1. Thirty-one male golden-mantled ground squirrels were divided into four physiological groups: low wt summer, medium wt summer, high wt summer and hibernation period. A second group of 10 females was divided into two groups: hibernation period at low T_b and hibernation period during a periodic arousal.
• 2.2. Blood serum, pancreas and antral stomach region were collected from each animal.
• 3.3. The serum was analysed by radioimmunoassay for pancreatic polypeptide immunoreactivity, the pancreas for pancreatic polypeptide and somatostatin immunoreactivity and the antral region of the stomach for gastrin immunoreactivity.
• 4.4. Significant between-stage differences (P < 0.05) were found in serum pancreatic polypeptide concentration and in pancreatic somatostatin content.

     

The effect of time on physiological changes in eel Anguilla anguilla,induced by lindane

• 1.1. Eel were exposed to a sublethal concentration of lindane (0.335 ppm) for 6, 12, 24, 48, 72 and 96 hr.
• 2.2. Concentrations of glycogen, glucose, lactate, pyruvate and lipids were determined in gill tissue after lindane exposure.
• 3.3. Gill glycogen descreased and glucose levels increased at 6 hr of treatment, lactate and pyruvate concentration increased between 6 and 48 hr. Total lipid values decreased between 6 and 24 hr; thereafter, the levels increased up to 72 hr of exposure.
• 4.4. Clear changes were found in all parameters tested in gill tissues. The observed effects of lindane on metabolism in fish are discussed in relation to acute stress syndrome.

     

Glycogen phosphorylase in lobster hepatopancreas: action of proteases on the enzyme

• 1.1. In lobster hepatopancreas, extracellular protreases cause the inactivation of glycogen phosphorylase.
• 2.2. The proteolysis of glycogen phosphorylase purified from rabbit muscle by these proteases has been shown by SDS-polyacrylamide gel electrophoresis.
• 3.3. A cell isolation technique has allowed us to remove proteases of extracellular digestion and to measure glycogen phosphorylase activity in lobster hepatopancreas.
• 4.4. The glycogen phosphorylase activity seems to be mainly associated with R cells while it could not be detected in B cells.

     

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.

     

A novel inhibitor of glycogen phosphorylase from crayfish hepatopancreas

• 1.1. A novel glycogen phosphorylase inhibitor was partially purified from crayfish hepatopancreas.
• 2.2. The inhibitor was found only in two species of crayfish examined, and not in lobster, fresh and salt water clams, mussels or cockroaches.
• 3.3. The inhibitor is a small protein (M_r = 23,000) which did not show proteolytic activity.
• 4.4. Preliminary kinetic analysis of the inhibitory mechanism indicated that it bound to both glycogen and the glycogen phosphorylase protein.
• 5.5. Inhibitor binding to glycogen resulted in a competitive inhibition pattern with respect to glycogen phosphorylase (inhibition constant of ca 10 μg/ml).
• 6.6. The inhibitor also bound glycogen phosphorylase directly with a binding coefficient of 100 μg/ml resulting in a partially non-competitive inhibition pattern with respect to phosphate.

     

Influence of handling and/or anaesthesia on stress response in rainbow trout. Effects on liver primary metabolism

• 1.1. The overall effect of handling, anaesthesia and sham injection on some blood metabolites, liver glycogen and several key enzymes involved in liver carbohydrates and nitrogen metabolism was studied in rainbow trout. In addition, the possible role of anaesthesia (MS222) itself as a stress-inductor or suppressor was also studied.
• 2.2. Stress resulted in hyperglycaemia and initially in liver glycogen depletion, as well as increasing plasma amino acid levels.
• 3.3. Glycogen stores subsequently recovered while amino acid concentration fell.
• 4.4. These changes seemed to correlate with the increased activity of liver fructose 1,6-bisphosphatase, glucose 6-phosphate dehydrogenase, alanine aminotransferase and glutamate dehydrogenase, thus supporting the hypothesis that gluconeogenic flux from amino acids increases in stressed trouts.
• 5.5. Anaesthesia, under the same experimental conditions, did not seem to mediate in stress production, but rather resulted in stress suppression.

     

Seasonal effects of prolactin on aspects of carbohydrate and lipid metabolism in the goldfish,Carassius auratus

• 1.1. Diurnal and seasonal variations of certain aspects of carbohydrate and lipid metabolism to ovine prolactin (PRL) treatment in the goldfish, Carassius auratus, were examined.
• 2.2. PRL treatment late in the light phase of a long photoperiod during spring depletes liver glycogen stores. During fall liver glycogen levels are not affected by PRL treatment in fishes acclimated to long or short photoperiods. PRL is hypoglycaemic in fall and spring.
• 3.3. PRL administered late in the light phase of a long photoperiod during spring increases plasma and liver total lipids and plasma cholesterol, while decreasing plasma triglycerides. In fall PRL may increase or decrease plasma organic-bound P levels dependent upon injection time.

     

Study on α-glucosidases in four human colon malignant tumors developed into nude mice

• 1.1. Both acid and neutral α-glucosidases are characterized in 4 human adenocarcinoma tumors obtained from SW-480, HCT-8R, HRT-18, HT-29 cell-lines of different glycogen content, by using either 4-methyl-umbelliferyl-α-d-glucoside (MUαG) or glycogen and maltose as substrate.
• 2.2. No obvious linear relationship between glucosidases activity and glycogen level can be found; however, the lowest and highest activities coincide with the lowest and highest glycogen contents respectively.
• 3.3. The hydrolytic activity of neutral glucosidase investigated in the presence of turanose as inhibitor of the acid form, is found to be high towards MUαD or maltose, but weak towards glycogen.
• 4.4. Kinetic parameters for both enzymes are found to be similar in the 4 tumors under investigation and close to what was reported in normal animal tissues.