Physiological processes

Compounds other than nutrients which afTect physiological processes in plants. E.g. auxins, gibberellins. 

Among vertebrate species, the neuro-endocrine-immime system is responsible for many complex, inter-related physiological processes including neuronal, homeostatic, reproductive and immune functions. There are four main types of hormone polypeptides, eicosanoids, steroids and thyroid hormones. Reflecting the inter-dependency of the neiiro-endocrine and immune systems, hormones, neuropeptides and other neiirotransmitters are known to be produced by some immune cells and play a role in the regulation of the immune system, while endocrine and nervous tissues express receptors for many substances produced by the immune system. The major focus of interest in endocrine disruption has... 

Table 13,1 Examples of physiological processes mediated by G proteins...

Biology Physiological processes (e.g., digestion and metaholismj, hacterial growth... 

Respiration Physiological process of taking in oxygen and expelling oxida-... 

Thermoregulation Physiological process attempting to maintain body core... 

LJreolysis Physiological process that breaks down urea and releases ammonia. 

The basis for believing the pharmacological intervention can be a major approach to the treatment of disease is the fact that the body generally functions in response to chemicals. Table 1.1 shows partial lists of hormones and neuro transmitters in the body. Many more endogenous chemicals are involved in normal physiological function. The fact that so many physiological processes are controlled by chemicals provides... 

Prostaglandins are a group of lipid autacoids known as eicosanoids. They are produced from membrane phospholipids and found in almost every tissue and body fluid. They are involved in a number of physiological processes including inflammation, smooth muscle tone and gastrointestinal secretion. In the central nervous system they have been reported to produce both excitation and inhibition of neuronal activity. 

Most drugs can be expected to have potentially lethal effects, as their usefulness depends on their ability to infiuence physiological processes. However, the dose level at which toxic effects manifest should be significantly higher than those required to produce a pharmaceutical response, so that a good safety margin exists between therapeutic and toxic levels. 

Proteins themselves consist of large molecules with several hundred amino acids in the primary stmcture. Smaller units, known as polypeptides, may be formed during physiological processes. There is no clear distinction between a protein and a polypeptide about 200 amino acid units in the primary stmcture is usually taken to be the minimum for a substance to be considered a protein. 

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