The effect of sodium monofluoroacetate on plasma testosterone concentration in Tiliqua rugosa (gray)

• 1.1. Administration of multiple or single doses of sodium fluoroacetate (1080) to male Tiliqua rugosa caused a decrease in plasma testosterone concentration.
• 2.2. A single dose of 100 or 250 mg 1080 kg⁻¹ body weight decreased plasma testosterone by 52%. However, 25 mg kg⁻¹ had little apparent effect on testosterone levels. When lizards were given the multiple dose equivalent of these doses over 12 days at 3 day intervals, the effect was much less dramatic with plasma testosterone concentration steadily declining over 15 days for the two higher doses.
• 3.3. There was a suggestion of degeneration of seminiferous tubules in some individuals.

     

Activity of some enzymes involved in the metabolism of polyamines in the liver of streptozotocin-diabetic rats

• 1.1. The effect of diabetes on some enzymes of polyamine metabolism was studied in male rats 1–12 days after administration of streptozotocin.
• 2.2. Hepatic ornithine decarboxylase activity decreased in the first days after the administration, but increased thereafter. The decrease was not due to an alteration of the ODC-antizyme concentration, nor to a posttranslational modification catalyzed by transglutaminase.
• 3.3. S-adenosylmethionine decarboxylase and ornithine transaminase were both increased.
• 4.4. Spermicline acetyltransferase activity was practically unchanged, while its inactivating factor was markedly decreased.

     

Immobilization stress-induced antioxidant defense changes in rat plasma: Effect of treatment with reduced glutathione

• 1.1. We examined immobilization stress-induced antioxidant defense changes in rat plasma and observed the antioxidant effect of reduced glutathione (GSH) administration on these changes.
• 2.2. Immobilization stress induced severe bleeding in the stomach and a significant increase in plasma levels of thiobarbituric acid receives substances (TBARS).
• 3.3. Immobilization stress induced a significant decrease in plasma iron-binding, ironoxidizing protections and radical scavenging activity.
• 4.4. Plasma levels of ascorbic acid, ascorbyl radical and superoxide dismutase activity remained unchanged following immobilization stress.
• 5.5. Treatment with GSH showed a significant protective effect on stomach bleeding, on the increase in plasma TEARS, and on the decrease of iron-binding, iron-oxidizing protection and radical scavenging activity in plasma.
• 6.6. These results suggest that immobilization stress induces generation of reactive oxygen species and decreases the endogenous antioxidant defenses, which can be attenuated by extracellular administration of antioxidant GSH.

     

Rat hypothalamic noradrenaline levels following midbrain raphé nuclei lesions

• 1.1. Electrolytic lesions of the median and dorsal raphé nuclei resulted in statistically significant reductions in rat hypothalamic noradrenaline which were observed 1 or 2 days after lesioning, while no changes were observed 7 or 14 days after lesioning.
• 2.2. The short term (1–2 days) raphé nuclei lesions produced no changes in hypothalamic 5-hydroxytryptamine or a small reduction in 5-hydroxyindole acetic acid while the expected marked reductions were observed after 7 days.
• 3.3. The reduction in hypothalamic noradrenaline observed after short term raphé nuclei lesions suggests the existence of a positive feedback loop between 5-hydroxytryptamine neurons and noradrenaline terminals in the hypothalamus.

     

Effects of recombinant salmon growth hormone on hypophysectomized male Fundulus heteroclitus

• 1.1. Recombinant salmon growth hormone at doses of 0.8 and 2.1 μg/g significantly enhanced linear growth in hypophysectomized male killifish, Fundulus heteroclitus, over that of controls and a significant regression was found between growth and the logarithm of dose.
• 2.2. Bovine growth hormone elicited significant growth enhancement at all three dosages tested (1,4 and 10 μg/g) and a significant log/dose relationship was also observed.
• 3.3. Observations on the relative weight of the gonads indicate that whole salmon pituitary extract (25 μg/g) possesses strong gonadotropic activity and that both bGH and rsGH had smaller but significant effects on the gonads.
• 4.4. It is suggested that growth hormone may play a subsidiary synergistic role to other pituitary hormones in gonadal development.

     

Hypocalcemic factor in the ultimobranchial gland of the frog,Rana rugosa

• 1.1. The hypocalcemic activity of the ultimobranchial gland of the frog, Rana rugosa, was estimated using a rat bioassay method.
• 2.2. Extracts of the ultimobranchial gland showed a very high hypocalcmic activity. The value corresponded to 6,340 mU (MRC)/kg b.w.
• 3.3. Serum inorganic phosphorus values of rats received the extract decreased in proportion to the dose, although no changes were found in serum sodium concentration.

     

Distribution of enzymes of cGMP metabolism in glomeruli and tubules isolated from normal and nephrotic rat kidney cortex

• 1.1. Puromycin aminonucleoside (PA) nephrosis may constitute a good experimental model to investigate the involvement of the cGMP system in the regulation of several kidney functions and especially glomerular permeability.
• 2.2. After a single intravenous injection of PA we studied the evolution of the guanylate cyclase (GCase) and cGMP-phosphodiesterase (G-PDE) activities in pure preparations of glomeruli (Gl) and tubules (TU).
• 3.3. Both Gl and TU homogenates showed a strong increase of the GCase activity 12 days after PA injection.
• 4.4. In the presence of Triton X-100, TU homogenate GCase showed the same pattern as in absence of this detergent while the Gl enzyme decreased unexpectedly. On the other hand, the only G-PDE change was observed in the TU where this activity decreases progressively.
• 5.5. Gl pellets and TU supernatants showed similar changes as in total homogenates. But, compared to the total homogenate, both Gl and TU supernatant GCases were strongly activated and in the Gl these activation rates were not the same in normal and 12 days-nephrotic rats.
• 6.6. These results could be explained by the existence of a membrane bound GCase “effector” involved in the physiopathological evolution of the disease.
• 7.7. In conclusion it seems to be clear that the cGMP-system is involved in the evolution of PA-nephrosis. But the precise relation between variations in the cGMP-system and the disease remains unclear and needs further investigation.

     

The effect of cortisol on stimulation of enzymatic activity and absorption of amino acids in the small intestine of adult hamsters

• 1.1. The s.c. administration of cortisol to hamsters (50 mg/kg body wt/day for 4 days) produces a significant increase in maltase sucrase, alkaline phosphatase and leucineaminopeptidase activity in intestinal mucosa.
• 2.2. Lactase activity is unaffected by cortisol.
• 3.3. Gamma-glutamyltranspeptidase activity increases slightly in females but remains unchanged in males.
• 4.4. Cortisol causes increase in proline and glycine absorption without changing the absorption of lysine.

     

Ontogeny of type I and type III deiodinase activities in embryonic and posthatch chicks: Relationship with changes in plasma triiodothyronine and growth hormone levels

• 1.1. The ontogeny of type I and type III deiodinase activities was studied in embryonic and posthatch chicks.
• 2.2. Hepatic type I activity showed a 3-fold increase up to the period of pipping and hatching and decreased slowly thereafter.
• 3.3. Hepatic type III activity increased by 3-fold from E14 to E17 and decreased more than 10-fold from E17 to CO. Posthatch levels were very low.
• 4.4. Type I activity in the kidney decreased slowly after hatching while type III activity was very low over the whole period studied.
• 5.5. Developmental changes during the late embryonic period suggest a causal relationship between the increase in plasma GH and T₃ levels and the decrease in hepatic type III activity.

     

The effects of osmotic stressors on the stenohaline carp (Cyprinus carpio)

• 1.1. Carp were acclimatized to different concentration of urea and mannitol.
• 2.2. The fish survived in 300 mOsm urea and 262 mOsm mannitol for a longer period. Higher concentrations were only tolerated for a short time.
• 3.3. Urea penetrated into the animals. The internal concentration of urea in plasma was nearly equal to the outside concentration after 7 days. Therefore a very high internal osmolality was adjusted (sum of normal and urea osmolality).
• 4.4. Urea treatment only resulted in changes of Ca level, while the concentration of other electrolytes was not clearly varied.
• 5.5. Extracellular space of muscle was reduced while the intracellular space remained unchanged after urea treatment.
• 6.6. Mannitol treatment resulted in changes of electrolyte concentrations due to dehydration.
• 7.7. After 1 day of treatment the concentration of Na in plasma decreased which might indicate the limitation of tolerance.
• 8.8. Immediate shrinkage of ICS and, later, reduction of ECS were clear reactions to mannitol influence.

     

Stearyl-CoA desaturation capacity of the rat liver during regeneration after partial hepatectomy

• 1.1. Stearyl-CoA desaturase activity was measured in microsomes isolated from regenerating rat liver over a period of 11 days.
• 2.2. The stearyl-CoA desaturation capacity of the liver recovered by the fourth day after partial hepatectomy.
• 3.3. Return to normal enzyme activity coincided with the normalization of the ratio between stearic and oleic acids in microsomes.

     

Long-term starvation in Xenopus laevis daudin—III. Effects on enzymes in several tissues

• 1.1. Adult, female Xenopus laevis were subjected to 12 months of starvation.
• 2.2. Starvation resulted in a continuous reduction in the activity of both hepatic and renal glucose-6-phosphate dehydroganse.
• 3.3. Fructose-1,6-diphosphatase was significantly reduced at months 10 and 12 in the liver, and at months 4, 10, and 12 in the kidney.
• 4.4. Pyruvate kinase activity of muscle and liver decreased during the experimental period whereas the renal enzyme remained essentially unchanged.
• 5.5. Both hepatic and renal glutamate-pyruvate transaminase (GPT) and hepatic glutamate-oxaloacetate transaminase (GOT) showed a reduction of activity after 2 and 4 months of starvation followed by an increase in GPT but not in GOT.

     

Involvement of lysine residue in the nucleotide binding of pigeon liver malic enzyme: modification with affinity label periodate-oxidized nadp

• 1.1. Periodate-oxidized NADP, a competitive inhibitor of malic enzyme with respect to NADP. inactivate the enzyme in mild conditions.
• 2.2. The inactivation is due to the modification of an essential lysine residue.
• 3.3. Two molecules of reagent were found to be incorporated into the enzyme tetramer after extensive modification.
• 4.4. Complete protection of malic enzyme from the oxidized NADP inactivation was afforded by NADP and its analogues.
• 5.5. The modified enzyme showed increased apparent Michaelis constant for the nucleotide coenzymes but the maximum velocity was decreased.
• 6.6. The binding between the modified enzyme and NADPH was impaired.

     

Role of the visceral nerve in heart rate variations during different behavioral patterns in Megalobulimus sanctipauli (mollusca,gastropoda, pulmonata)

• 1.1. The role of the visceral nerve in mediating the changes in heart rate associated with different behavioral patterns was investigated in Megalobulimus sanctipauli.
• 2.2. The results of acute and chronic denervation experiments indicate that the visceral nerve has no excitatory or inhibitory tonic action on the heart of snails retracted into the shell, nor does it account for the increase in heart rate associated with the locomotion and feeding behaviors.
• 3.3. These changes in heart rate are, probably, indirect effects of increased activity such as an increase in venous return.
• 4.4. The visceral nerve is responsible for approximately 3/4 of the increase in heart rate associated with the first minute of extrusion.
• 5.5. The small increase in heart rate observed in denervated animals is probably caused by an increase in venous return generated by muscle activity that forces the head and food out of the shell.

     

In vivo effect of Berenil on rat liver polyamine metabolism

• 1.1. Berenil, administered to rats in vivo, promoted a decrease in liver SAMDC activity, but an increase in ODC and SAT activity.
• 2.2. Its effect on ODC was completely prevented by cycloheximide, that on SAT only partially.
• 3.3. Berenil had no effect on ODC activity in adrenalectomized rats. Adrenergic antagonists counteracted the effect of Berenil on ODC activity.
• 4.4. Polyamine content was increased. The maximum modification was observed for putrescine and N¹-acetylspermidine.

     

Structure and bioelectricity of single neurons of Helix pomatia in the intact nervous tissue during epileptic activity: Simultaneous evaluations by confocal microscopy and intracellular recordings of membrane potential changes

• 1.1. Neuronal shape during epileptic activity was studied with confocal laser scanning microscopy and intracellular recording of identified neuronal individuals in the buccal ganglia of Helixpomatia. Simultaneous observations of single Lucifer Yellow stained fibers and epileptic activity of the same neuron were done.
• 2.2. During epileptic activity, the development of several types of morphological changes were observed: local and extended swellings, constrictions, stretching of neuronal processes and release of intracellular material.
• 3.3. Morphological alterations did not only occur with epileptic activity but could also appear due to extended laser exposure of fluorescent neuronal processes.
• 4.4. Phototoxicity is discussed as a limiting factor for a valid interpretation of the morphological changes observed by confocal microscopy.

     

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.

     

Activity of NAD-sorbitol dehydrogenase is caused by biosynthesis of enzyme protein in diapause and non-diapause eggs of the silkworm,Bombyx mori

• 1.1. Using SDS-PAGE and immunoblotting analyses with anti-sorbitol dehydeogenase (EC 1.1.1.14, SDH) serum, changes in amount of SDH protein were examined in diapause and non-diapause eggs of the silkworm, Bombyx mori.
• 2.2. When diapause eggs were exposed to 5°C from 2 days after oviposition to break the diapause gradually, SDH protein appeared after 50-day chilling, and then the amount increased along with chilling period. This changing pattern paralleled that in SDH activity.
• 3.3. In diapause eggs treated with HCl after chilling at 5°C for 30 days to break the diapause quickly, and non-diapause eggs, changing patterns in amount of SDH protein also paralleled those in SDH activity.
• 4.4. These results showed that SDH activity was caused by biosynthesis of SDH protein, independent of diapause or non-diapause eggs.
• 5.5. Occurrence of SDH correlates with the three developmental phases: diapause termination, embryonic growth, and larval differentiation. In larva, SDH was mainly localized in the fat-body.

     

Effect of repetitive cortisol and thyroxine injections on chloride cell number and Na+/K+-ATPase activity in gills of freshwater acclimated rainbow trout,Salmo gairdneri

• 1.1. Freshwater nonanadromous rainbow trout, Salmo gairdneri, were injected three times a week with either saline, 10μg cortisol/g, 1.0μg thyroxine/g or 10μg cortisol/g + 1.0μg thyroxine/g during a period of 28 days (12 injections). A separate group was derived as a subgroup from the thyroxine group on day 14 and received Cortisol + thyroxine from day 14 until day 28 (six injections).
• 2.2. Gill chloride cell number and Na⁺/K⁺-ATPase activity increased by cortisol treatment, the changes being significant on days 7 and 14, respectively.
• 3.3. Thyroxine treatment did not affect gill Na⁺/K⁺-ATPase activity or chloride cell number directly. Neither did it modify the stimulatory effect of cortisol on these parameters.
• 4.4. Muscle water decreased in cortisol-treated fish and increased in thyroxine-treated fish, while no changes were observed in the combined hormone groups.
• 5.5. No changes were observed in plasma chloride in any group during the experiment.
• 6.6. The results demonstrate a putative role of cortisol in stimulating hypo-osmoregulatory mechanisms and suggest that thyroxine is without a direct or a supportive effect for cortisol action.

     

In vitro non-enzymatic glycosylation of myofibrillar proteins

• 1.1. Glycation is non-enzymatic modification of proteins by sugars in which not only structural but also biological properties of proteins are altered.
• 2.2. Our in vitro experiments show that incubation of myofibrillar proteins with ribose results in sugar attachment to proteins and at the same time myofibrillar ATPase activity is lowered.
• 3.3. DETAPAC, aminoguanidine and 2-mercaptoethanol all partially block myofibrillar protein glycation and ATPase activity is less inactivated.
• 4.4. The dependence of ATPase activity of myofibrils incubated with ribose on the amount of 2-mercaptoethanol present suggests that also modification of SH groups is involved in enzyme inactivation.
• 5.5. Electrophoretic studies revealed that heavy chains of myosin, actin, and tropomyosins are proteins which are mainly glycated in vitro.