"Pesticides Induced Changes In Circulating Thyroid Hormones In The Freshwater Catfish Clarias Batrachus" By Sinha Et. Al., Demonstrates The Importance Of Environmental Awareness In Endocrinology

Fasting-induced changes in thermogenic responses to norepinephrine (NE, 4.0 micrograms X kg-1 X min-1 iv) were studied in anesthetized rats previously cold acclimated. The rats were divided into five groups at the end of 30–40 days of cold acclimation (5 degrees C). The five groups were kept for 5 days at 25 degrees C and fed (intact fed), fasted (intact fasted), fasted with daily treatment with thyroxine (T4, 2 micrograms/kg sc), thyroidectomized and fed, or thyroidectomized and fasted. In the intact fasted group, in which the weight of brown adipose tissue decreased, NE-induced increases in oxygen consumption, colonic temperature (T col), and temperature of the interscapular brown adipose tissue (TBAT) were markedly suppressed. The two thyroidectomized groups also showed a reduction in thermogenic response. In these three groups, TBAT was lower than Tcol throughout NE infusion. In the T4-treated fasted group, fasting-induced suppression of thermogenic response to NE was largely prevented. In the intact fed and the T4-treated fasted groups, TBAT attained higher values than Tcol during NE infusion. Plasma levels of thyroid hormones were significantly lower in the intact fasted group than in the intact fed or the T4-treated fasted group. These results suggest that fasting-induced suppression of the thermogenic response to NE is largely due to the reduced thermogenic response of brown adipose tissue to NE. The lowering of the levels of the thyroid hormones induced by fasting may be one of a number of causes of the reduction in the thermogenic response of brown adipose tissue.

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γ-BHC- and Cythion-induced alterations in lipid metabolism in a freshwater catfish, Clarias batrachus, during different phases of its annual reproductive cycle

Ecotoxicology and Environmental Safety ◽

10.1016/0147-6513(87)90081-9 ◽

1987 ◽

Vol 14 (1) ◽

pp. 38-47 ◽

Cited By ~ 4

Author(s):

B. Lal ◽

T.P. Singh

Keyword(s):

Lipid Metabolism ◽

Reproductive Cycle ◽

Clarias Batrachus ◽

Annual Reproductive Cycle ◽

Freshwater Catfish

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Kinetics of Thyroid Hormone Induced Changes in Liver and Skeletal Muscle Enzymes of Clarias batrachus

Zeitschrift für Naturforschung C ◽

10.1515/znc-1999-5-624 ◽

1999 ◽

Vol 54 (5-6) ◽

pp. 458-462 ◽

Cited By ~ 1

Author(s):

G. Tripathi

Keyword(s):

Skeletal Muscle ◽

Lactate Dehydrogenase ◽

Malate Dehydrogenase ◽

Metabolic Enzymes ◽

Time Dependent ◽

Clarias Batrachus ◽

Muscle Enzymes ◽

Induced Changes ◽

Kinetics Of ◽

Mitochondrial Malate Dehydrogenase

Abstract Kinetics of triiodothyronine (T3) induced changes were studied in cytoplasmic malate dehydrogenase (cMDH), mitochondrial malate dehydrogenase (mMDH) and lactate dehydrogenase (LDH) of the liver and skeletal muscle of a catfish, Clarias batrachus. The rates of gradual inductions in the activities of all the three metabolic enzymes were faster in skeletal muscle than those of the liver. These time-dependent and tissue-specific inductions may be due to the possible differences in the rates of different enzymic syntheses. The maximum inductions in the activities of cMDH, mMDH and LDH were recorded around 19 hr after T3 treatment. Thereafter, the activities of all the enzymes gradually declined to their half levels within the next 12 hr which reflected the physiological half-life of these metabolic enzymes in the freshwater catfish.

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