Influence of acclimation temperature on rate constants for thyroid uptake of iodide by brook trout, Salvelinus fontinalis (Mitchill)

1971 ◽  
Vol 49 (5) ◽  
pp. 783-786 ◽  
Author(s):  
Carolyn D. Smith ◽  
J. G. Eales
Keyword(s):  
Rate Constant ◽  
Rate Constants ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Acclimation Temperature ◽  
Thyroid Activity ◽  
Iodide Uptake ◽  
Individual Fish ◽  
Thyroid Uptake

A procedure for determining the rate constant for thyroid iodide uptake for fish is described.Rate constants for thyroid iodide uptake in brook trout agreed with previously used indices of thyroid activity (T/S and CR) in indicating a more active thyroid at 16C than 10C.At both temperatures radioiodide metabolism was extremely slow with considerable variation between individual fish. These features may be attributed to the high and variable serum stable iodide level in this species.

The influence of temperature on histological and radiochemical measurements of thyroid activity in the eastern brook trout, Salvelinus fontinalis Mitchell

1968 ◽  
Vol 46 (1) ◽  
pp. 1-9 ◽  
Author(s):  
D. E. Drury ◽  
J. G. Eales
Keyword(s):  
Epithelial Cell ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Acclimation Temperature ◽  
Thyroid Follicle ◽  
Thyroid Activity ◽  
Cell Height ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
T Values

Histological and radiochemical techniques for assessing thyroid activity were compared on yearling brook trout acclimated at 5, 12, and 15 °C.The mean thyroid follicle epithelial cell height was 7.4 μ (range 6.0–8.6 μ) at 5 °C; 3.5 μ (range 2.9–3.9 μ) at 12 °C, and 2.3 μ (range 1.9–2.9 μ) at 15 °C. Assuming that a taller epithelial cell height indicates greater thyroid activity, then an inverse relationship between thyroid activity and acclimation temperature exists.Both the uptake of radioiodide by the thyroid (T/S) and the clearance of radioiodide from the serum were greater at higher temperatures. Serum PB125I production was negligible within 8 days after radioiodide injection and the conversion ratio could not be applied as an index of thyroid function, Assuming, however, that the thyroid radioiodide uptake is an index of thyroid activity, then there is a direct relationship between thyroid activity and acclimation temperature.In view of the marked discrepancy between these histological and radiochemical techniques, fractional rates of turnover of serum thyroxine were compared by determining the biological half-life (t½) for serum PB125I after L-thyroxine-125I intraperitoneal injection at different temperatures. The serum PB125I clearance curves were complex and tentative t½ values of 18.0 days (5 °C, 3.2 days (12 °C), and 1.5 days (15 °C) were obtained. These results indicate a more rapid serum PBI turnover at higher temperatures and support the radiochemical measurements.

scholarly journals Molecular and physiological responses predict acclimation limits in juvenile brook trout (Salvelinus fontinalis)

2021 ◽  
Vol 224 (16) ◽  
Author(s):  
Theresa E. Mackey ◽  
Caleb T. Hasler ◽  
Travis Durhack ◽  
Jennifer D. Jeffrey ◽  
Camille J. Macnaughton ◽  
...  
Keyword(s):  
Heat Shock ◽  
High Temperatures ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Acute Stress ◽  
Physiological Responses ◽  
Heat Shock Protein 90 ◽  
Acclimation Temperature ◽  
Muscle Lactate ◽  
Air Exposure

ABSTRACT Understanding the resilience of ectotherms to high temperatures is essential because of the influence of climate change on aquatic ecosystems. The ability of species to acclimate to high temperatures may determine whether populations can persist in their native ranges. We examined physiological and molecular responses of juvenile brook trout (Salvelinus fontinalis) to six acclimation temperatures (5, 10, 15, 20, 23 and 25°C) that span the thermal distribution of the species to predict acclimation limits. Brook trout exhibited an upregulation of stress-related mRNA transcripts (heat shock protein 90-beta, heat shock cognate 71 kDa protein, glutathione peroxidase 1) and downregulation of transcription factors and osmoregulation-related transcripts (nuclear protein 1, Na+/K+/2Cl− co-transporter-1-a) at temperatures ≥20°C. We then examined the effects of acclimation temperature on metabolic rate (MR) and physiological parameters in fish exposed to an acute exhaustive exercise and air exposure stress. Fish acclimated to temperatures ≥20°C exhibited elevated plasma cortisol and glucose, and muscle lactate after exposure to the acute stress. Fish exhibited longer MR recovery times at 15 and 20°C compared with the 5 and 10°C groups; however, cortisol levels remained elevated at temperatures ≥20°C after 24 h. Oxygen consumption in fish acclimated to 23°C recovered quickest after exposure to acute stress. Standard MR was highest and factorial aerobic scope was lowest for fish held at temperatures ≥20°C. Our findings demonstrate how molecular and physiological responses predict acclimation limits in a freshwater fish as the brook trout in the present study had a limited ability to acclimate to temperatures beyond 20°C.

Iodide and thyroxine metabolism in the brook trout, Salvelinus fontinalis (Mitchill), during sustained exercise

1971 ◽  
Vol 49 (9) ◽  
pp. 1255-1269 ◽  
Author(s):  
D. A. Higgs ◽  
J. G. Eales
Keyword(s):  
Thyroid Hormone ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Specific Activity ◽  
Hormone Secretion ◽  
Conversion Ratio ◽  
Limited Extent ◽  
Thyroid Activity ◽  
Individual Variations ◽  
Serum Ratio

Iodide and thyroxine metabolism were followed in exercised and non-exercised starved trout.Radioiodide (125I) parameters suggested a slight increase in thyroid activity (% dose in thyroid, thyroid/serum ratio (T/S), and conversion ratio (CR)) and an increase in extrathyroidal 125I excretion resulting from exercise.The generally high and variable serum 127I levels increased up to 496 μg% during the experiments, being consistently higher in exercised fish. Individual variations in serum 127I were related in many instances to radioiodide parameters (I125I, T/S, CR) and to a limited extent to % thyroid. This demonstrates the uncertainty of radioiodide measurements when the specific activity of circulating 125I changes and the need for assessing 127I levels in radioiodide studies.Tissue uptake of radioactivity and serum loss of protein-bound radioactivity following radiothyroxine intraperitoneal injection, as well as serum stable thyronine levels, suggested both increased biliary loss of thyroid hormones and a higher thyroid hormone secretion rate as the result of exercise.

scholarly journals Molecular and physiological responses predict acclimation limits in juvenile brook trout (Salvelinus fontinalis)

2020 ◽  
Author(s):  
Theresa E. Mackey ◽  
Caleb T. Hasler ◽  
Travis Durhack ◽  
Jennifer D. Jeffrey ◽  
Camille J. Macnaughton ◽  
...  
Keyword(s):  
Heat Shock ◽  
Metabolic Rate ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Transcript Abundance ◽  
Acclimation Temperature ◽  
Temperature Threshold ◽  
Plasma Parameters ◽  
Muscle Lactate ◽  
Air Exposure

AbstractBrook trout (Salvelinus fontinalis) populations are at risk of exposure to high water temperatures in the species’ native range in eastern North America. We quantified the physiological and molecular responses of juvenile brook trout to six acclimation temperatures that span the thermal distribution of the species (5, 10, 15, 20, 23, and 25°C). Using quantitative PCR (qPCR), we measured the mRNA transcript abundance of temperature-induced cellular stress genes to identify a potential sub-lethal temperature threshold for brook trout between 20–23°C. Brook trout exhibited an upregulation of stress-related genes (heat shock protein 90-beta; heat shock cognate 71 kDa protein; glutathione peroxidase 1) and a downregulation of transcription factors and osmoregulation-related genes (Na+/K+/2Cl− co-transporter-1-a; nuclear protein 1) at temperatures ≥20°C. We also used respirometry to assess the effects of the acclimation temperatures on oxygen consumption. Standard metabolic rate results indicated that energy expenditure was higher at temperatures ≥20°C. We then examined the effects of acclimation temperature on metabolic rate and blood plasma parameters in fish exposed to an acute exhaustive exercise and air exposure stress. Fish acclimated to temperatures ≥20°C exhibited elevated levels of plasma cortisol, muscle lactate, and plasma glucose after exposure to the acute stressors. After 24 h of recovery, fish showed longer metabolic recovery times at 15 and 20°C and cortisol levels remaining elevated at temperatures ≥20°C. Our findings suggest that brook trout may have a limited ability to acclimate to temperatures >20°C and increases in temperatures beyond 20°C may impact brook trout populations.

Downstream Movement and Mortality of Brook Trout (Salvelinus fontinalis) Exposed to Acidic Episodes in Streams

1994 ◽  
Vol 51 (7) ◽  
pp. 1620-1628 ◽  
Author(s):  
Charles J. Gagen ◽  
William E. Sharpe ◽  
Robert F. Carline
Keyword(s):  
Adverse Effects ◽  
Water Samples ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Low Ph ◽  
Stream Discharge ◽  
Individual Fish ◽  
Dead Fish ◽  
Lower Stream ◽  
Downstream Movement

Episodes of low pH and high Al concentration were associated with net downstream movement and increased mortality of ratio-tagged brook trout (Salvelinus fontinalis). We compared movements of 10–15 brook trout in two streams with severe acidic episodes with movements of fish in two streams with less severe acidic episodes (reference streams). Study populations moved downstream hundreds of metres in the streams with more severe acidic episodes (pH <5.0 and >200 μg Al/L). Median downstream movement in spring was 250 and 900 m after 20 d for fish in the more acidic streams; one third of the fish were found dead during this time. We found no net movement and no dead fish in the reference streams. Lower stream discharge in fall studies was associated with less severe acidic episodes, less net movement, and no mortality. Water samples collected at individual fish locations indicated that few fish avoided adverse effects of acidic episodes by remaining in microhabitats with higher pH and lower Al concentration.

CHANGES IN THYROID ACTIVITY DURING GROWTH IN THE SHEEP

1961 ◽  
Vol 22 (1) ◽  
pp. 23-30 ◽  
Author(s):  
I. R. FALCONER ◽  
H. A. ROBERTSON
Keyword(s):  
Body Weight ◽  
Energy Metabolism ◽  
Thyroid Hormone ◽  
Rate Constants ◽  
Hormone Secretion ◽  
Secretion Rate ◽  
Initial Increase ◽  
Thyroid Activity ◽  
Thyroid Uptake ◽  
Unit Body Weight

SUMMARY The rate constants for thyroid uptake (K1) and release (K4) of 131I, the serum protein-bound iodine (PBI) level and the rate of secretion of thyroid hormone have been determined for sheep from 5 weeks to 7 years old. The secretion rate of thyroid hormone has been shown to increase rapidly up to the age of 6–8 months, and then decline slightly with increasing age. The rate constant for 131I release from the thyroid (K4), showed an increase up to 1 year of age, and considerably lower values at 5 and 7 years old. When the thyroid hormone secretion rate is expressed per unit body weight, the highest rate was observed at approx. 6 months of age or 20–40 kg. body weight. The significance of this initial increase in thyroid hormone secretion rate per unit body weight is discussed in conjunction with the results of other workers on the energy metabolism of immature animals. Serum PBI levels decreased sharply during the 1st year of life and then remained relatively constant.

Determination of rate constants of redox reactions of second order from current-less potential-time curves by a simplified graphical-numerical method

1983 ◽  
Vol 48 (5) ◽  
pp. 1358-1367 ◽  
Author(s):  
Antonín Tockstein ◽  
František Skopal
Keyword(s):  
Numerical Method ◽  
Explicit Form ◽  
Rate Constant ◽  
Optimization Algorithm ◽  
Rate Constants ◽  
Redox Reactions ◽  
Second Order ◽  
Wide Region ◽  
Recurrent Formula

A method for constructing curves is proposed that are linear in a wide region and from whose slopes it is possible to determine the rate constant, if a parameter, θ, is calculated numerically from a rapidly converging recurrent formula or from its explicit form. The values of rate constants and parameter θ thus simply found are compared with those found by an optimization algorithm on a computer; the deviations do not exceed ±10%.

The Effect of p-Toluidine on the Two-Step Electroreduction of Zn(II) in Water-Methanol and Water-Dimethylformamide

1999 ◽  
Vol 64 (4) ◽  
pp. 585-594 ◽  
Author(s):  
Barbara Marczewska
Keyword(s):  
Electron Transfer ◽  
Binary Mixtures ◽  
Rate Constant ◽  
Rate Constants ◽  
Electrode Surface ◽  
Mercury Electrode ◽  
Forward Rate ◽  
Solvent Molecules ◽  
Activated Complex

The acceleration effect of p-toluidine on the electroreduction of Zn(II) on the mercury electrode surface in binary mixtures water-methanol and water-dimethylformamide is discussed. The obtained apparent and true forward rate constants of Zn(II) reduction indicate that the rate constant of the first electron transfer increases in the presence of p-toluidine. The acceleration effect may probably be accounted for by the concept of the formation on the mercury electrode an activated complex, presumably composed of p-toluidine and solvent molecules.

Radiolysis studies on the corrosion inhibitors 1 -hexyn-3-ol, cinnamonitrile, and 1,3-diethyl-2-thiourea

1995 ◽  
Vol 73 (12) ◽  
pp. 2137-2142 ◽  
Author(s):  
A.J. Elliot ◽  
M.P. Chenier ◽  
D.C. Ouellette
Keyword(s):  
Hydrogen Atom ◽  
Hydroxyl Radical ◽  
Temperature Dependence ◽  
Rate Constant ◽  
Rate Constants ◽  
Corrosion Inhibitors ◽  
Hydrated Electron

In this publication we report: (i) the rate constants for reaction of the hydrated electron with 1-hexyn-3-ol ((8.6 ± 0.3) × 108 dm3 mol−1 s−1 at 18 °C), cinnamonitrile ((2.3 ± 0.2) × 1010 dm3 mol−1 s−1 at 20 °C), and 1,3-diethyl-2-thiourea ((3.5 ± 0.3) × 108 dm3 mol−1 s−1 at 22 °C). For cinnamonitrile and diethylthiourea, the temperature dependence up to 200 °C and 150 °C, respectively, is also reported; (ii) the rate constants for the reaction of the hydroxyl radical with 1-hexyn-3-ol ((5.5 ± 0.5) × 109 dm3 mol−1 s−1 at 20 °C), cinnamonitrile ((9.2 ± 0.3) × 109 dm3 mol−1 s−1 at 21 °C), and diethylthiourea ((8.0 ± 0.8) × 108 dm3 mol−1 s−1 at 22 °C). For cinnamonitrile, the temperature dependence up to 200 °C is also reported; (iii) the rate constant for the hydrogen atom reacting with 1-hexyn-3-ol ((4.3 ± 0.4) × 109 dm3 mol−1 s−1 at 20 °C). Keywords: radiolysis, corrosion inhibitors, rate constants.

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