Liver Protein Kinase Activity and Triiodothyronine

Roques, M; Tirard, Alain; DeGroot, Leslie J.; Rapaud, J.

doi:10.1210/endo-100-4-967

Cited by 24 publications

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“…protein kinases (26)(27)(28). To help determine whether thyroid status affects the metabolism of cAMP or its subsequent action, DBcAMP was added to the medium perfusing livers from hypothyroid, hyperthyroid, and euthyroid rats.…”

Section: Expmentioning

confidence: 99%

Modulation by Thyroid Status of the Actions of Glucagon and Dibutyryl Adenosine 3′,5′-Monophosphate on Metabolism of Free Fatty Acids by the Isolated Perfused Rat Liver*

et al. 1982

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The interactions among effects of thyroid status, glucagon, and dibutyryl cAMP (DBcAMP) on the regulation of hepatic metabolism of FFA were studied in perfused livers isolated from euthyroid, hypothyroid, and hyperthyroid male rats. The animals were made hypothyroid by treatment with propylthiouracil or hyperthyroid by treatment with T 3 . Uptake of oleic acid by perfused livers was not altered by treatment of the animal with T3 or propylthiouracil, or by addition to the medium of glucagon (10~9 M), DBCAMP (2 X 10~5 M), or methylisobutylxanthine (MIX; 2 HIM). In agreement with previous data, hepatic formation and secretion of triglyceride were diminished and ketogenesis was stimulated by hyperthyroidism, glucagon, and DBcAMP. These effects of diminished triglyceride output and enhanced ketogenesis observed in hyperthyroidism were exacerbated by glucagon, while livers from hypothyroid rats were insensitive to the effects of glucagon. MIX, a phosphodiesterase inhibitor, reversed the insensitivity of the livers from hypothyroid rats to the effects of glucagon. DBcAMP stimulated ketogenesis and inhibited triglyceride output by livers in the three treatment groups. The effects of DBcAMP were not modulated by thyroid status under the conditions of these experiments. The effects of glucagon on hepatic triglyceride concentration were qualitatively similar to those effects on perfusate triglyceride. DBcAMP did not affect hepatic triglyceride concentration in any of the treatment groups. Glucagon stimulated glucose output by livers from all treatment groups but was less effective with livers from hypothyroid rats than from euthyroid animals. DBcAMP stimulated glucose output from all treatment groups. It may be concluded from these data that thyroid status modulates the sensitivity of the liver to glucagon, as evaluated by metabolism of FFA. Because 2 mM MIX reversed the insensitivity of hypothyroid livers to 10~9 M glucagon, it is possible that the mechanism (s) through which thyroid hormones and glucagon interact to affect hepatic fatty acid metabolism may, in part, be mediated through pathways of cAMP metabolism, perhaps by altering the activity of hepatic cyclic nucleotide phosphodiesterase. (Endocrinology 110: 1740(Endocrinology 110: , 1982 I T WAS REPORTED in previous studies from this laboratory that although uptake of FFA by the isolated perfused rat liver was not altered by thyroid status (2, 3), glucagon (4, 5), or dibutyryl cAMP (DBcAMP; 6, 7), the subsequent metabolism of FFA was profoundly affected. Output of triglyceride was diminished, whereas ketogenesis was stimulated by T3, glucagon, and

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Section: Expmentioning

confidence: 99%

Modulation by Thyroid Status of the Actions of Glucagon and Dibutyryl Adenosine 3′,5′-Monophosphate on Metabolism of Free Fatty Acids by the Isolated Perfused Rat Liver*

et al. 1982

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“…Thyroid hormone is known to increase casein kinase activity in rat liver cytosol (Roques, Tirard and DeGroot 1977;Pavlovic-Hournac, Delbauffe and Ohayon1978;Nakamura, Rue and DeGroot 1983). Our recent studies show that casein kinase activity increases significantly 24 hours post T 3 -injection (500 Mg of T 3 /100 g BW).…”

Section: + + U) +mentioning

confidence: 91%

cAMP-Independent Casein Kinase Mediates Phosphorylation of Many T₃-Dependent Phosphoproteins in Rat Liver Cytosol

Nakamura¹,

DeGroot²

1984

Horm Metab Res

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Administration of T3 (20 micrograms/100 g BW) for 3 days increases phosphorylation of several proteins in rat liver cytosol in vitro. To help elucidate the mechanism of T3-induced phosphorylation, we studied which protein kinase(s) mediate phosphorylation of endogenous cytosolic proteins. Five different protein kinases were obtained by DEAE+ cellulose column chromatographic fractionation of liver cytosol. When their ability to phosphorylate heat-inactivated cytosol was investigated, casein kinase, a cAMP independent protein kinase, showed the strongest effect. Casein kinase, purified by phosphocellulose chromatography, phosphorylated more than 10 cytosolic proteins. Several T3-dependent (and cAMP independent) phosphoproteins were included among these. One protein with Mr 39 X 10(3), of which phosphorylation is stimulated by T3 within five hours after injection, was the most active substrate for casein kinase. The results suggest that casein kinase is the enzyme responsible for phosphorylation of many rat liver cytosolic proteins and that several phosphoproteins, apparently under T3-regulation, might be phosphorylated by this enzyme.

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Casein kinase II activity in the brain of an insect,Acheta domesticus: Characterization and hormonal regulation

Degrelle¹,

Renucci²,

Charpin³

et al. 1997

Arch. Insect Biochem. Physiol.

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Liver Protein Kinase Activity and Triiodothyronine

Cited by 24 publications

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Modulation by Thyroid Status of the Actions of Glucagon and Dibutyryl Adenosine 3′,5′-Monophosphate on Metabolism of Free Fatty Acids by the Isolated Perfused Rat Liver*

Modulation by Thyroid Status of the Actions of Glucagon and Dibutyryl Adenosine 3′,5′-Monophosphate on Metabolism of Free Fatty Acids by the Isolated Perfused Rat Liver*

cAMP-Independent Casein Kinase Mediates Phosphorylation of Many T₃-Dependent Phosphoproteins in Rat Liver Cytosol

Casein kinase II activity in the brain of an insect,Acheta domesticus: Characterization and hormonal regulation

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Liver Protein Kinase Activity and Triiodothyronine

Cited by 24 publications

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Modulation by Thyroid Status of the Actions of Glucagon and Dibutyryl Adenosine 3′,5′-Monophosphate on Metabolism of Free Fatty Acids by the Isolated Perfused Rat Liver*

Modulation by Thyroid Status of the Actions of Glucagon and Dibutyryl Adenosine 3′,5′-Monophosphate on Metabolism of Free Fatty Acids by the Isolated Perfused Rat Liver*

cAMP-Independent Casein Kinase Mediates Phosphorylation of Many T3-Dependent Phosphoproteins in Rat Liver Cytosol

Casein kinase II activity in the brain of an insect,Acheta domesticus: Characterization and hormonal regulation

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cAMP-Independent Casein Kinase Mediates Phosphorylation of Many T₃-Dependent Phosphoproteins in Rat Liver Cytosol