Biomaterial Database

Effect of cold exposure on phosphoenolpyruvate carboxykinase (GTP) activity and cyclic amp concentration in livers of starved rats. Role of glucorticoids. 1976

W Krone, and W B Huttner, and H J Seitz, and W Tarnowski

The effect of cold exposure (5 degrees C) on the concentration of cyclic AMP and on the activity of phosphoenolpyruvate carboxykinase (GTP: oxaloacetate carboxy-lyase (transphosphorylating), EC 4.1.1.32) was investigated in the liver of intact and adrenalectomized starved rats. Intact starved rats responded to cold exposure with a large increase in both the concentration of hepatic cyclic AMP and the activity of phosphoenolpyruvate carboxykinase above the starvation level. Adrenalectomy did not impair the cold-induced maximum elevation of cyclic AMP but totally prevented the response of the enzyme to cold. Yet, this response was completely restored by hydrocortisone treatment, while the steroid per se had no effect on enzyme activity. In isolated perfused livers of intact starved rats dibutyryl cyclic AMP provoked an immediate dramatic increase in phosphoenolpyruvate carboxykinase activity above the starvation level even if mRNA synthesis was inhibited by cordycepin. However, cyclic AMP was ineffective in increasing enzyme activity in livers of adrenalectomized rats. From these results it is suggested (i) that in starved rats the adaptation to the enhanced glucose demand provoked by cold exposure includes the induction of hepatic phosphoenolpyruvate carboxykinase above the starvation level, (ii) that this induction is due to the cold-induced increase in hepatic cyclic AMP levels, (iii) that cyclic AMP stimulates enzyme synthesis at a post-transcriptional step and (iv) that the cold-induced cyclic AMP-mediated induction of phosphoenolpyruvate carboxykinase above the starvation level requires the "permissive" effect of glucocorticoids.

UI	MeSH Term	Description	Entries
D007328	Insulin	A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).	Iletin,Insulin A Chain,Insulin B Chain,Insulin, Regular,Novolin,Sodium Insulin,Soluble Insulin,Chain, Insulin B,Insulin, Sodium,Insulin, Soluble,Regular Insulin
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008297	Male		Males
D010729	Phosphoenolpyruvate Carboxykinase (GTP)	An enzyme of the lyase class that catalyzes the conversion of GTP and oxaloacetate to GDP, phosphoenolpyruvate, and carbon dioxide. This reaction is part of gluconeogenesis in the liver. The enzyme occurs in both the mitochondria and cytosol of mammalian liver. (From Dorland, 27th ed) EC 4.1.1.32.	GTP-Dependent Phosphoenolpyruvate Carboxykinase,Carboxykinase, GTP-Dependent Phosphoenolpyruvate,GTP Dependent Phosphoenolpyruvate Carboxykinase,Phosphoenolpyruvate Carboxykinase, GTP-Dependent
D001786	Blood Glucose	Glucose in blood.	Blood Sugar,Glucose, Blood,Sugar, Blood
D003080	Cold Temperature	An absence of warmth or heat or a temperature notably below an accustomed norm.	Cold,Cold Temperatures,Temperature, Cold,Temperatures, Cold
D003839	Deoxyadenosines	Adenosine molecules which can be substituted in any position, but are lacking one hydroxyl group in the ribose part of the molecule.	Adenine Deoxyribonucleosides,Adenylyldeoxyribonucleosides,Deoxyadenosine Derivatives,Deoxyribonucleosides, Adenine,Derivatives, Deoxyadenosine
D003994	Bucladesine	A cyclic nucleotide derivative that mimics the action of endogenous CYCLIC AMP and is capable of permeating the cell membrane. It has vasodilator properties and is used as a cardiac stimulant. (From Merck Index, 11th ed)	Dibutyryl Adenosine-3',5'-Monophosphate,Dibutyryl Cyclic AMP,(But)(2) cAMP,Bucladesine, Barium (1:1) Salt,Bucladesine, Disodium Salt,Bucladesine, Monosodium Salt,Bucladesine, Sodium Salt,DBcAMP,Dibutyryl Adenosine 3,5 Monophosphate,N',O'-Dibutyryl-cAMP,N(6),0(2')-Dibutyryl Cyclic AMP,AMP, Dibutyryl Cyclic,Adenosine-3',5'-Monophosphate, Dibutyryl,Cyclic AMP, Dibutyryl,Dibutyryl Adenosine 3',5' Monophosphate,Disodium Salt Bucladesine,Monosodium Salt Bucladesine,N',O' Dibutyryl cAMP,Sodium Salt Bucladesine
D006160	Guanosine Triphosphate	Guanosine 5'-(tetrahydrogen triphosphate). A guanine nucleotide containing three phosphate groups esterified to the sugar moiety.	GTP,Triphosphate, Guanosine
D006889	Hydroxycorticosteroids	A group of corticosteroids carrying hydroxy groups, usually in the 11- or 17-positions. They comprise the bulk of the corticosteroids used systemically. As they are relatively insoluble in water, salts of various esterified forms are often used for injections or solutions.