Hormones tissue

Once they have elicited the appropriate action in their target tissue, hormones... 

Figure 25-7. Metabolism of adipose tissue. Hormone-sensitive lipase is activated by ACTH, TSH, glucagon, epinephrine, norepinephrine, and vasopressin and inhibited by insulin, prostaglandin E, and nicotinic acid. Details of the formation of glycerol 3-phosphate from intermediates of glycolysis are shown in Figure 24-2. (PPP, pentose phosphate pathway TG, triacylglycerol FFA, free fatty acids VLDL, very low density lipoprotein.)...

As to the primary developmental actions of testosterone, growth and differentiation appear to be involved. Testosterone or estradiol stimulates outgrowth of neurites from developing hypothalamic neurons that contain estrogen receptors [14, 15]. This is believed to be one of the principal aspects of testosterone action that increases the number and the size of neurons within specific hypothalamic nuclei in males, compared to females [1, 14, 15]. 5a-DHT may have a similar effect on androgen-sensitive neurons. Differentiation of target neurons also occurs in adult brain tissue, hormones like estradiol can evoke responses that differ between adult male and female rats [1,14,15],... 

Hormones are chemical signaling substances. They are synthesized in specialized cells that are often associated to form endocrine glands. Hormones are released into the blood and transported with the blood to their effector organs. In the organs, the hormones carry out physiological and biochemical regulatory functions. In contrast to endocrine hormones, tissue hormones are only active in the immediate vicinity of the cells that secrete them. 

Hormones transfer signals by migrating from their site of synthesis to their site of action. They are usually transported in the blood. In this case, they are said to have an endocrine effect (1 example insulin). By contrast, tissue hormones, the target cells for which are in the immediate vicinity of the glandular cells that produce them, are said to have a paracrine effect (2 example gastrointestinal tract hormones). When signal substances also pass effects back to the cells that synthesize them, they are said to have an autocrine effect (3 example prostaglandins). Autocrine effects are often found in tumor cells (see p. 400), which stimulate their own proliferation in this way. 

Histamine, an important mediator (local signaling substance) and neurotransmitter, is mainly stored in tissue mast cells and basophilic granulocytes in the blood. It is involved in inflammatory and allergic reactions. Histamine liberators such as tissue hormones, type E immunoglobulins (see p. 300), and drugs can release it. Histamine acts via various types of receptor. Binding to Hi receptors promotes contraction of smooth muscle in the bronchia, and dilates the capillary vessels and increases their permeability. Via H2 receptors, histamine slows down the heart rate and promotes the formation of HCl in the gastric mucosa. In the brain, histamine acts as a neurotransmitter. 

The underlying mechanism may involve the adipose tissue hormone leptin or immune modulators such as tumor necrosis factor alfa. 

LVA cardiac tissue, hormone mide, nickel (high function, reduced pain... 

The main source of serotonin (5-HT) is the enterochromaffin cells, which release it as tissue hormone either into the gut lumen or the portal vein circulation. In the CNS, cell bodies of 5-HT-containing neurons are concentrated along the raphe nuclei of the brainstem and are also found in more lateral regions and in the reticular formation. The neurons terminate in almost all brain regions and in the spinal cord. 

Plasma kinins are tissue hormones liberated from a-globulins of the blood plasma by kallikrein. 

Shirley, J.F., Emery, R.S., Convey, E.M., Oxender, W.D. 1973. Enzymic changes in bovine adipose and mammary tissue, serum and mammary tissue hormonal changes with initiation of lactation. J. Dairy Sci. 56, 569-574. 

Proteohormones, steroid hormones and peptide hormones may be differentiated on the basis of their chemical structure. Hormones may be classified as neurosecretory (e. g. hypothalamus), glandular (endocrine glands) or aglandular according to their source tissue. Aglandular hormones are also known as tissue hormones they are synthesized in special cells located in specific organs. Hormones may be differentiated according to their transport characteristics into unbound hormones and hormones which are coupled to a carrier protein. A further classification is based on their principal functions, (s. tab. 3.9)... 

Guerre-Milo M. Adipose tissue hormones. J Endocrinol Invest 2002 25(10) 855 61. 

J.K. Huttunen and D. Steinberg, Activation and phosphorylation of purified adipose tissue hormone-sensitive lipase by cyclic AMP-dependent protein kinase, Biochim. Biophys. Acta, 1971, 239, 411-427. 

REUBI, J.C., KRENNING, E., LAMBERTS, S.W.J., KVOLS, L., Somatostatin receptors in malignant tissues. Hormonal Manipulation of Cancer Peptides, Growth Factors and New (Anti) Steroidal Agent (Proc. 2nd Int. EORTC Symp.), Pergamon Press, Oxford, UK (1990) 1073-1077. 

A survey of the functions of type 2 copper proteins reveals that all are directly involved in oxygen metabolism (oxidases, oxygenases, superoxide dismutases). Many of these functions are only relevant for multicellular organisms (synthesis of connective tissue, hormone synthesis). It can therefore be assumed that type 2 proteins occurred after the oxygenation of the atmosphere or with the development of multicellular organisms. There is no phylogenetic relationship between type 1 and type 2 copper proteins. 

Hormonal regulation integrates responses in pathways requiring more than one tissue. Hormones generally regulate fuel metabolism by ... 

Cyclic AMP is synthesized by the membrane-bound enzyme adenylate cyclase which is present in almost all mammalian tissues. Hormonal regulation of adenylate cyclase is initiated by the hormone binding to cell surface receptors. The resulting hormone-receptor complex Interacts with either stimulatory regulatory proteins, (Ns), or inhibitory regulatory proteins, (Nl), which bind guanine nucleotides and Interact with the catalytic subunit (C) of adenylate cyclase to modulate the enzyme activity. 

The differences in the tissue hormone concentrations in various animals and the dissimilarities in the age changes of the tissue levels may be related to the fact that the presence of hormones in the endocrine glands presumably is chiefly the result of genetic factors. For the survival of an animal species, adequate biochemical functions are required only to ensure continuation of life until the reproductive stage has been reached. It may be presumed that several other biological features merely are the consequences of evolutionary coincidences they have been classified as evolutionary freaks or evolutionary relics by some biologists. 

It must be admitted that some tissue hormone observations, as for instance the presence of prolactin and oxytocin in the male pituitary gland are diflScult to interpret on the assumption of a meaningful function of the hormone. The possibility exists, however, that the presence in animal bodies of phylogenetically conditioned extraordinary hormones and hormone concentrations may exert unfavorable metabolic effects. For this reason, detailed studies on the tissue levels of all types of hormones would seem to be indicated. 

De Niu P, Radman D, Jaworski E, et al. (2000) Development of a human stanniocalcin radioimmunoassay serum and tissue hormone levels and pharmacokinetics in the rat. Molecular and Cellular Endocrinology 162 131-144. 

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