Hormonal control of metabolism

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

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. 

Hormone control of metabolism is regulated by chemical messengers secreted into the blood by different endocrine glands. These messengers, called hormones, travel to other tissues or organs, where they may stimulate or inhibit specific metabolic pathways. 

A classic example of hormonal control of metabolism is the hormone adrenaline, which is secreted by the... 

Energy expenditure is relatively constant throughout the day, but food intake normally occurs in two or three meals. There is therefore a need for metabolic regulation to ensure that there is a more or less constant supply of metabolic fuel to tissues, regardless of the variation in intake. See section 10.5 for a more detailed discussion of the hormonal control of metabolism in the fed and fasting states. 

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... 

However, the control of metabolism appears to be more complicated than this as it also involves the hypothalamus and pituitary gland. It seems that the male hypothalamus produces a factor, which inhibits the release of a hormone and which therefore leaves the liver in a particular male state. In the female, the hypothalamus is inactive, and therefore produces no factor, and hence the pituitary releases a feminizing factor (possibly growth hormone), which changes the liver to the female state. 

Hormonal control of lipid metabolism in the small intestine. 

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... 

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). ... 

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. 

Hormonal Control of Copper Metabolism Recent evidence suggests that metabolism of copper as well as zinc is controlled by the pituitary-adrenal axis (97,98,99). For example, administration of large doses of corticosteroids in humans leads to rapid and sustained drop in serum copper and zinc. Pregnant women and women on oral contraceptive agents show a significant increase in serum copper levels (iOO, 101,102),... 

The physiological functions of hormones have been broadly categorized into those that (1) affect growth and development, (2) exert homeostatic control of metabolic pathways, and (3) regulate the production, use, and storage of energy. The descriptions below illustrate examples of these functions and mechanisms of control of hormone secretion. 

Hormones are molecules organisms use to convey information between cells. When target cells are distant from the hormone-producing cell, such molecules are called endocrine hormones. To ensure proper control of metabolism, the synthesis and secretion of many mammalian hormones are regulated by a complex cascade mechanism ultimately controlled by the central nervous system. In addition, a negative feedback mechanism precisely controls various hormone syntheses. A variety of diseases are caused by either overproduction or underproduction of a specific hormone or by the insensitivity of target cells. 

The reversible covalent modification of enzymes is important in control of metabolism, cell growth and division, response to hormones, and other processes. Examples of the types of reversible side-chain modifications found in cells include ... 

Short-term hormonal control of protein phosphatases involved in hepatic glycogen metabolism, W. Stalmans, M. Bollen, B. Toth, and P. Gergely, 1990, Adv. Enzyme Reg., 305327. 

ATP + glycogen phosphorylase <1> (conversion to an AMP-independent form, key enzyme of neural and hormonal control of glycogen metabolism) [29]... 

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