Acute stress suppresses plasma estradiol levels in female alligators (Alligator mississippiensis)

• 1.1. Five adult, female alligators (Alligator mississippiensis) were captured at night during the breeding season, and a blood sample taken within 5 min of capture.
• 2.2. The alligators were physically restrained (tied to boards) and additional blood samples taken at 4, 8, 12, 16, 22, 28, 38, and 48 hr after capture. After the last blood sample was collected the animals were released.
• 3.3. Plasma estradiol-17β and corticosterone were measured by radioimmunoassay. Estradiol declined significantly from initial values by 22 hr post capture, but remained unchanged for 48 hr.
• 4.4. Plasma corticosterone rose from a mean of 0.8 ng/ml at capture to 12.6 ng/ml after 4 hr. Corticosterone continued to rise up to 16 hr then declined after 22 hr. From 28 until 48 hr corticosterone again increased significantly.
• 5.5. These results demonstrate that acute stress in female alligators causes significant suppression of plasma estradiol and a biphasic pattern of corticosterone secretion.

     

Sex-specific androgen binding in spotted hyaena (Crocuta crocuta) plasma

• 1.1. A charcoal adsorption assay demonstrated a large variance in androgen binding ability in female spotted hyaenas.
• 2.2. A positive correlation between plasma androgen binding ability and ovarian steroid concentrations was demonstrated in adult females.
• 3.3. The strong plasma binding affinity for testosterone and dihydrotestosterone (DHT) (nM) together with the lack of cortisol and weaker oestradiol-17β binding suggests that a specific androgen binding substance, possibly a protein, is present in adult females of this species.
• 4.4. The lack of high affinity binding in male spotted hyaenas is unusual and deserves further investigation.
• 5.5. Some androgen binding in all, including males and immature animals suggests that albumin may bind some plasma androgens in this species.

     

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.

     

Influence of sex hormones on the chick gastrointestinal transit and emptying

• 1.1. Gastrointestinal (GI) transit and emptying of male and female 15-day-old chickens treated with testosterone, estradiol and progesterone was measured by means of ¹⁴C-polyethylene glycol-4000.
• 2.2. All the administered sex hormones increased GI motility at the shortest time (0.5 and 1 hr) after the marker administration, but decreased GI motility at the longest times (2 and 4 hr). This motor pattern agrees with the known anabolic role of sex hormones.
• 3.3. We conclude that testosterone and estradiol increased GI motility and intestinal inhibitory reflexes. Thus, chicks' and mammals' GI motility were modified by testosterone and estradiol in a similar form.
• 4.4. The effect of progesterone on the chick GI motility was contrary to that observed in mammals. This may happen because of increased inhibitory GI motor reflexes or direct inhibition of visceral smooth muscle activity.
• 5.5. No statistical differences were observed between the sexes, which could be explained by the sexual immaturity of chicks.
• 6.6. Chicks constitute good biological material to study the influence of sex hormones on avian GI motility.

     

Environmental and genetic influences on the thermal physiology of Rana sylvatica

• 1.1.|Intraspecific variation in the thermal physiology of Rana sylvatica was examined.
• 2.2.|Heat and cold tolerances of both adult and larval representatives were determined for animals representing populations from New York, Maryland, Kentucky, Ohio, Michigan and Canada.
• 3.3.|In general, frogs from more northern localities exhibited lower heat tolerances.
• 4.4.|There was no evidence of interpopulational differences in cold tolerance. Similar trends were revealed by larval testing.
• 5.5.|Interpopulational differences among laboratory-reared tadpoles suggests a strong genetic component to Rana sylvatica thermal physiology.

     

Induction of a 60-kDa heat shock protein in rat pancreas by water-immersion stress

• 1.1. In this study, expression of a 60-kDa heat shock protein in rat pancreas was investigated before and after water-immersion stress, which has been known as an exacerbation factor of caerulein-induced pancreatitis in rats, by Western blot.
• 2.2. A 60-kDa heat shock protein increased after water-immersion stress in both soluble and insoluble fractions of the pancreas.
• 3.3. Serum amylase level and pancreas weight did not increase after water-immersion.
• 4.4. No pathologic alteration was observed in the pancreas after water-immersion.

     

Flight-induced increase in circulating levels of melatonin in the homing pigeon

• 1.1. Homing pigeons, receiving regular flight-training for participation in racing competitions, were flown from their usual release site, 48 km away from “home”.
• 2.2. On their return “home” within 60–80 min, blood samples for the measurement of melatonin were taken within 1–3 min of arrival.
• 3.3. Post-flight circulating levels of melatonin were found to be about 82% higher than those of the resting control pigeons without any change in plasma osmolality.
• 4.4. This daytime increase in circulating levels of melatonin suggests that melatonin, by virtue of its known hypothermic effect of facilitating peripheral heat dissipation, could prevent excessive flight-induced hyperthermia.
• 5.5. It is also suggested that the flight-induced increase in plasma levels of melatonin is consistent with the known analgesic and metabolic effects of the hormone.

     

A relationship between circulating natural glucocorticoids and the mechanical responses of the heart in atricial and precocial rodents

• 1.1. A comparison was made of the mechanical performance of heart muscle from mouse, an atricial mammal, with corticosterone as glucocorticoid and spiny mouse (Acomys cahirinus), a precocial mammal, with cortisol as glucocorticoid.
• 2.2. Force-frequency responses were negative in mouse and positive in spiny mouse.
• 3.3. During recovery, there was a gradual increase and an overshoot in the mouse, while in the spiny mouse there was an initial enhanced response, diminishing gradually with time.
• 4.4. High calcium concentration inhibited contractile tension in mouse heart, while it was positively inotropic in spiny mouse heart. Changes in the concentration of calcium did not change the patterns of force-frequency response.
• 5.5. Lowering the experimental temperature increased the time course and amplitude of the tension curve. However, various parameters exhibited different temperature sensitivity.
• 6.6. There was a significant difference in the levels of circulating cortisol between male and female spiny mice.
• 7.7. It is proposed that the differences in the mechanical responses of mouse and spiny mouse hearts may be explained in terms of the effects of the specific glucocorticoid hormone on the development of the sodium-calcium exchanger.

     

Plasma lipid transport in the horse (Equus caballus)

• 1.1. Equine plasma contains lipoproteins corresponding to very low density (VLDL), low density (LDL) and high density lipoproteins (HDL).
• 2.2. HDL accounts for approximately 60% of plasma lipoprotein mass and consists of a single population of particles.
• 3.3. LDL is heterogeneous comprising three discrete subfractions.
• 4.4. Two proteins are found in the region of apolipoprotein (apo) B-100 in VLDL and LDL and a third similar to apo B-48 is in VLDL.
• 5.5. Lecithin:cholesterol acyl transferase is active in plasma and hepatic lipase and lipoprotein lipase are evident in post-heparin plasma.
• 6.6. There is no significant cholesteryl ester transfer protein activity.

     

Distribution of beta-adrenergic binding in fractionated porcine adipocytes

• 1.1. The subcellular distribution of the porcine adipocyte beta-adrenergic receptor was studied in fractionated adipocytes.
• 2.2. The 30,000 g pellet obtained from hypotonically lysed cells contained membrane vesicles and mitochondria; it yielded approx 200–300 fmol dihydroalprenolol-bound receptors/mg protein.
• 3.3. Activity was increased to about 1000 fmol/mg protein after isolation of a plasma membrane fraction on a Percoll gradient.
• 4.4. The 5'-nucleotidase, succinate dehydrogenase and lactate dehydrogenase activities were usually enriched in compartments different from the ligand-binding activity.
• 5.5. Activity of porcine adipocyte 5'-nucleotidase, a purported plasma membrane marker enzyme, was not distributed in the same manner as the beta-adrenergic receptor.

     

Seasonal variation of LH and testosterone in the smallest deer,the pudu (Pudu puda molina) and its relationship to the antler cycle

• 1.1. In order to obtain a seasonal profile of LH, three adult male pudu (Pudu puda, Molina) were sampled monthly from the saphenous vein for a period of one year.
• 2.2. A significant circannual variation of plasma LH levels was detected with an average peak value (1.77 ng/ml) recorded in February and nadir concentrations (0.19 ng/ml) observed in November.
• 3.3. The peak level of testosterone (1.54 ng/ml) was detected in March, the time of the rut.

     

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.

     

Variations in tissue reserves,plasma metabolites and pancreatic hormones during fasting in immature carp (Cyprinus carpio)

• 1.1. Immature carp were subjected to 2-month fasting periods. Mobilization of reserves in liver and muscle, and the energy contribution of each reserve were studied. Changes in plasma glucose, amino acids, insulin and glucagon levels were determined throughout the experiment.
• 2.2. No changes were observed in plasma glucose, insulin or glucagon at 19 days of fasting, but plasma amino acids increased. At 50 days of fasting, both plasma glucagon and amino acids increased, liver glycogen decreased and muscle proteolysis began.
• 3.3. Between 50 and 67 days of fasting, plasma glucose and insulin decreased significantly, while glucagon and amino acids continued to increase. Strong muscular proteolysis was observed while liver glycogen stabilized.
• 4.4. The contribution of each reserve in liver and muscle to energy production throughout fasting is considered.

     

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.

     

Sympathoadrenal activity during helox-cold induced hypothermia in syrian hamsters

• 1.1. As reflected by increasing plasma concentrations of cortisol, norepinephrine, epinephrine and dopamine, a marked stimulation of the adrenal cortex and of the sympathetic nervous system occurred in Syrian hamsters during moderate hypothermia induced by helium-oxygen atmosphere and cold.
• 2.2. A profound hyperglycemia was observed during hypothermia.
• 3.3. All effects due to the helium-oxygen atmosphere and cold exposure (helox-cold) disappeared almost completely after rewarming.
• 4.4. The results corroborate the hypothesis of an involvement of the adrenal cortex combined with the sympathetic nervous system in the control of acute induced heat production.

     

Company news

Including information on:

• ScanSoft
• SpeechWorks International
• Viisage Technology
• Firstec
• BIO-key International
• HP
• ZN Vision Technologies
• Unisys
• US Government’s
• Communication Intelligence Corporation
• Infinity Technologies

     

Flight effects on certain blood parameters in homing pigeons Columba livia

• 1.1. Various blood parameters were monitored in resting and flown homing pigeons. A homing flight of 48 km lasting 60–80 min did not significantly alter plasma levels of total protein, electrolytes and plasma osmolality, which indicated maintenance of the homeostatic stability of the internal milieu during moderate exercise.
• 2.2. Plasma concentrations of marker enzymes such as alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), laetate dehydrogenase (LDH) and creatine phosphokinase (CPK) that tend to denote muscle damage and metabolic flux in prolonged exercise, were also not altered, thereby indicating the steady state of tissue structure and function during a flight of this magnitude.
• 3.3. Significant increases in plasma levels of uric acid and creatinine and decreases in plasma albumin were observed in the flown pigeons.
• 4.4. The flight-induced increase in blood uric acid could be attributed to increased purine catabolism and the increase in creatinine to increased nucleotide turnover.
• 5.5. It is suggested that the higher uric acid levels should not only enhance water conservation, but may also reduce flight-induced hyperthermia besides acting as an antioxidant defence against oxidative tissue injury.
• 6.6. The rise in creatinine is indicative of the breakdown of phosphocreatine for energy during the initial period of flight prior to the utilization of carbohydrate and lipid as fuels.
• 7.7. The decrease in plasma albumin should account for the albumin as lipid carrier lost in transport to the muscles during flight.

     

Company news

• Daon
• Musicrypt
• EMI Music Canada
• Digital Broadband Networks
• FaceKey Corporation
• Eystar Media Inc (EMI)
• Temasya Wira
• Animated Electronic Industries
• BIO-key International
• Entryport Corporation

     

The energetics of shedding: Energy content of snake skin

• 1.1. The weight and energy content of sloughed skins of 92 individual snakes of 22 different species in three families were measured.
• 2.2. Weight and total energy content of shed skins were highly correlated with body weight.
• 3.3. The heat of combustion (kJ/g) of sloughed skins varied significantly among families and was higher in species having unkeeled scales than in those with keeled scales.
• 4.4. The presence of keels significantly affected weight of skins, even when skin weight is adjusted for covariance with body weight.
• 5.5. Neither body weight nor ambient temperature significantly affected the heat of combustion of sloughed skins.
• 6.6. The energy content of shed skin, expressed as a proportion of daily metabolism, decreased with ambient temperature, but the effect is minimized in large snakes.
• 7.7. Small snakes expended relatively less energy in sloughed skins than large snakes when the expenditure is expressed in terms of total daily metabolized energy.

     

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.