Hormones epinephrine

Earl Sutherland of Vanderbilt University won the 1971 Nobel Prize in physiology or medicine for uncovering the role of cAMP as a second messenger in connection with his studies of the "fight or flight" hormone epinephrine (Section 27.6). 

Smooth muscle contractions are subject to the actions of hormones and related agents. As shown in Figure 17.32, binding of the hormone epinephrine to smooth muscle receptors activates an intracellular adenylyl cyclase reaction that produces cyclic AMP (cAMP). The cAMP serves to activate a protein kinase that phosphorylates the myosin light chain kinase. The phosphorylated MLCK has a lower affinity for the Ca -calmodulin complex and thus is physiologically inactive. Reversal of this inactivation occurs via myosin light chain kinase phosphatase. 

By the turn of the century the theory of chemical mediation of physiologic responses had gained some currency. There ensued in some laboratories an intense search for endogenous chemical modifiers of bodily responses. The first such agent to be isolated from mammalian tissue was the ubiquitous hormone, epinephrine—at that time known as adrenaline. This compound has played an important role in pharmacology as well as in medicinal chemistry. 

Tyrosine is structurally related to and derived from phenylalanine. It is the metabolic precursor to dopamine, an important neurotransmitter. Tyrosine is also the precursor to the hormones epinephrine and norepinephrine and to melanin, the pigment of skin. 

Adrenoceptors interact not only with norepinephrine but also with the adrenal medullary hormone epinephrine and a number of chemically related drugs. However, the responses produced by the drugs in different autonomic structures differ quantitatively or qualitatively from one another. 

Membrane Protein Topology The receptor for the hormone epinephrine in animal cells is an integral membrane protein (Mr 64,000) that is believed to have seven membrane-spanning regions. 

A cell in your adrenal gland has about 2.5 X 104 tiny compartments called vesicles that contain the hormone epinephrine (also called adrenaline). 

Electrodes next to an adrenal cell measure release of the hormone epinephrine. [Photo courtesy R. M. Wightman, University of North Caroiina ]... 

An elemental analysis of the hormone epinephrine is 59.0% carbon, 26.2% oxygen, 7.15% hydrogen, and 7.65% nitrogen by mass. When 0.64 g of epinephrine dissolved in 36.0 g of benzene, the freezing point decreased by 0.50°C. (a) Determine the empirical formula of epinephrine, (b) What is the molar mass of epinephrine (c) Deduce the molecular formula of epinephrine. 

The Hormone Epinephrine Stimulates Glucose Production in Both Liver Cells and Muscle Cells The Hormonal Regulation of the Flux between Fructose-6-phosphate and Fructose-1,6-bisphosphate Is Mediated by Fructose-2,6-bisphosphate... 

The Hormone Epinephrine Stimulates Glucose Production in Both Liver Cells and Muscle Cells... 

Use of Hormones in Nonendocrine Disease. There are many examples of how various hormones and hormone-related drugs can be used to treat conditions that are not directly related to the endocrine system. For instance, certain forms of cancer respond to treatment with glucocorticoids (see Chapter 36). Drugs that block the cardiac beta-1 receptors may help control angina and hypertension by preventing excessive stimulation from adrenal medulla hormones (epinephrine, norepinephrine see Chapters 21 and 22). 

C, D. Conjugated proteins. Prosthetic group. Hormones epinephrine, thyroxin, insulin, cortisone, ACTH. Chemotherapy. Arsphenamine, sulfanilamide and other sulfa drugs, penicillin, streptomycin, chloramphenicol, aiireomycin. Bacteriostatic action of sulfa drugs through competition with a bacterial growth substance, para-aminobenzoic acid. 

The initial event in the utilization of fat as an energy source is the hydrolysis of triacylglycerols by lipases, an event referred to as lipolysis. The lipase of adipose tissue are activated on treatment of these cells with the hormones epinephrine, norepinephrine, glucagon, and adrenocorticotropic hormone. In adipose cells, these hormones trigger 7TM receptors that activate adenylate cyclase (Section 15,1.3 ). The increased level of cyclic AMP then stimulates protein kinase A, -which activates the lipases by phosphorylating them. Thus, epinephrine, norepinephrine, glucagon, and adrenocorticotropic hormone induce lipolysis (Figure 22.6). In contrast, insulin inhibits lipolysis. The released fatty acids are not soluble in blood plasma, and so, on release, serum albumin binds the fatty acids and serves as a carrier. By these means, free fatty acids are made accessible as a fuel in other tissues. 

The hormone epinephrine (also known as adrenaline) is derived from which amino acid ... 

Methylation of norepinephrine in the adrenal medulla by S-adenosyl-g methionine forms the hormone epinephrine. 

---