Metabolism hormonal control

F17. Frayn, K. N., Hormonal control of metabolism in trauma and sepsis. Clin. Endocrinol. 24, 577-599(1986). 

Hormones have a profound effect on carbohydrate metabolism. Great interest has been aroused by reports of hormonal control of hexokinase activity by specific proteins in animal tissues.99- 100 Hexokinase action is the rate-limiting step in the uptake of D-glucose by muscle. Hexokinase is inhibited in diabetic muscle, but the inhibition can be partially reversed by insulin. A protein fraction from the anterior pituitary gland will inhibit the hexokinase of extracts of brain and muscle, and the effect of this... 

The main filtering units of the kidneys are called nephrons-, about one million nephrons are present in each kidney. Each nephron consists of a renal corpuscle and a unit called a tubule. Blood carrying normal metabolic wastes such as urea and creatine moves through a portion of the corpuscle called the glomerulus, where a filtrate forms that contains water, normal metabolic products, and also waste products the filtrate collects in another unit called Bowman s capsule. Glomerular filtrate then moves into a highly convoluted and multifaceted set of tubes - the tubule - where most useful products (water, vitamins, some minerals, glucose, amino acids) are taken back into the blood, and from which waste products are collected as urine. The relative amounts of water and minerals secreted or returned to the blood are under hormonal control. 

Hormones control, in part, metabolism. In general, hormones are molecules synthesized at one site in the body, travel to another site, and influence metabolism at the second site. Some of these hormones, though by no means all, are proteins. 

The kidneys main function is excretion of water and water-soluble substances (1). This is closely associated with their role in regulating the body s electrolyte and acid-base balance (homeostasis, 2 see pp.326 and 328). Both excretion and homeostasis are subject to hormonal control. The kidneys are also involved in synthesizing several hormones (3 see p. 315). Finally, the kidneys also play a role in the intermediary metabolism (4), particularly in amino acid degradation and gluconeo-genesis (see p. 154). 

E. Hormonal control provides a major means for regulation of metabolic pathways,... 

Figure 8-1. Hormonal regulation of fat metabolism. A Control of fatty acid synthesis by reversible phosphorylation of acetyl CoA carboxylase. B Regulation of tri-acylglycerol degradation by reversible phosphorylation of hormone-sensitive lipase. cAMP, cyclic adenosine monophosphate HS, hormone-sensitive.

Glucocorticoids are important metabolic hormones with a central role and many implications. They interact with nuclear receptors. The latter act on transcription factors of the genes coding proteins that are involved in the control of inflammation. 

Hormonal control of lipid metabolism in the small intestine. 

The control of glycogen phosphorylase by the phosphorylation-dephosphorylation cycle was discovered in 1955 by Edmond Fischer and Edwin Krebs50 and was at first regarded as peculiar to glycogen breakdown. However, it is now abundantly clear that similar reactions control most aspects of metabolism.51 Phosphorylation of proteins is involved in control of carbohydrate, lipid, and amino acid metabolism in control of muscular contraction, regulation of photosynthesis in plants,52 transcription of genes,51 protein syntheses,53 and cell division and in mediating most effects of hormones. 

Adipokinetic hormones control metabolism of insects during long-distance flight.359 363 In the migratory locust these hormones consist of a pair of related octapeptides and a decapeptide (Table 30-5). The hormones stimulate triacylglycerol lipase in the insects fat bodies, induce release of carbohydrates from body stores, and affect many other aspects of metabolism.363 Insects also have hormones of the insulin family, proteins consisting of disulfide-linked A and B chains as in insulin. The silkworm Bombyx mori has 38 genes for the insulinlike bombyxins, which are synthesized in the brain.364... 

Ho, D. T. Varner, J. E. Hormonal control of messenger ribonucleic acid metabolism in barleg aleurone layers. 

Hormonal control Glycogen metabolism is tightly controlled by hormones. When blood glucose by epinephrine levels fall, glucagon is secreted by the a cells of the pancreas and acts on the and glucagon liver to stimulate glycogen breakdown to glucose which is then released into... 

This means that CC will be regulated until CI=CO, so the system always ends up with perfect control no matter the gain. As shown later, many hormonal control systems and metabolic pathways utilize variants of integral control. Even some types of voluntary movements, for example length control via the muscle spindle, are dominated by integral control. 

At this point the history of the concept of hormonal control of insects should be recalled, since the major reasons for the selection of JH as a rational lead for pesticide design were the beliefs that JH occurred only in insects and not in other animals. The implication was that JH would therefore be selectively active in insects with no significant effects on other forms of life. In the cases of JH analogs of the farnesane skeleton, extensive studies of comparative toxicology have largely verified these beliefs. Toxicological results have been reviewed in detail (20 ) and a comprehensive study of the environmental fate and metabolism of methoprene has been completed (2 1). ... 

Hormonal Control of Metabolic Fuel Between your evening meal and breakfast, your blood glucose drops and your liver becomes a net producer rather than consumer of glucose. Describe the hormonal basis for this switch, and explain how the hormonal change triggers glucose production by the liver. 

At the outset, it appeared that proteinaceous products dispatched by a special class of neurosecretory neurons, such as those of the pars intercerebral is of insects, function exclusively in a neurohormonal capacity. Following the classical discovery by Kopec (1922) of a brain hormone controlling insect metamorphosis much information has been gained on a number of essential neurohormonal functions carried out by neuropeptides in the control of postembryonic development as well as reproductive, metabolic, muscular, and additional activities. 

Salter M and Pogson Cl (1985) The role of tryptophan 2,3-dioxygenase in the hormonal control of tryptophan metabolism in isolated rat liver cells. Effects of glucocorticoids and experimental diabetes. Biochemical Journal 229,499-504. 

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