Hormones examples

Figure 14-5 Recorded distributions of 100 blank and 00 sample values for the hypothetical hormone example. The estimated LoB (= 95th percentiie of the distribution of blank values) and the estimated LoD are indicated. SDs v/zs derived from the distribution of sample values (actually as a pooled estimate of sets of 10 measurements that are here merged together).

Hormones themselves may be proteins. Notable examples are the more well-known insulin and the lesser-known thyrotropin and somatotropin (the growth hormone), as well as the ovarian luteinizing hormone and the follicle-stimulating hormone. If of relatively low molecular weight, protein-type hormones are also known as peptides, or specifically as peptide hormones. Examples listed, as a matter of course, are adrenocorticotropin, antidiuretic hormone, glucagon, and calcitonin. (Generally speaking, a peptide is a molecule with fewer than 50 amino acids, and a protein has more than 50 amino adds. The acids are combined in myriad combinations or permutations.)... 

Terpenoids are also used as chemical messengers. If the communication is between different parts of the same organism, the messenger is referred to as a hormone. Examples of hormones are shown in Figure 1.8. Giberellic acid is a hormone used by plants to control their rate of growth. Testosterone and oestrone are mammalian sex hormones. Testosterone is a male hormone and oestrone, a female. 

The mechanism that regulates the production and secretion by an endocrine gland of its hormone, which, in turn, stimulates another endocrine gland to produce its hormone. Example The anterior pituitary secretes thyroid-stimulating hormone (TSH), which, in turn, stimulates the thyroid to secrete thyroxin. When the blood level of thyroxin reaches optimum, the anterior pituitary ceases to secrete TSH and, thereupon, the thyroid stops secreting thyroxin, and the blood level of thyroxin falls. 

The former theory that the primary effect consists in a direct interaction with certain enzymes (perhaps in the manner that vitamins act as components of coenzymes) has not been upheld for most hormones. Examples of quick responding metabolic regulation, such as the control of l lood glucose, depend in all likelihood on permeability changes of cell membranes. Another mechanism of action is seen in the stimulation of specific gene loci (Clever and Karlson). This promotes the production of messenger RNA and ultimately the synthesis of specific enzymes. The mechanism resembles that of enzyme induction in bacteria (cf. Fig. and also Chapt. VII-7). 

Hormone examples. The metal-binding properties of adrenaline, thyroxine, and histamine were mentioned in Section i i.i. 

Many pharmaceutical compounds contain chromophores that make them suitable for analysis by UV/Vis absorption. Products that have been analyzed in this fashion include antibiotics, hormones, vitamins, and analgesics. One example of the use of UV absorption is in determining the purity of aspirin tablets, for which the active ingredient is acetylsalicylic acid. Salicylic acid, which is produced by the hydrolysis of acetylsalicylic acid, is an undesirable impurity in aspirin tablets, and should not be present at more than 0.01% w/w. Samples can be screened for unacceptable levels of salicylic acid by monitoring the absorbance at a wavelength of... 

Control of secretion of anterior pituitary hormones also includes inhibition by hormones produced by target organs. For example, CRH stimulates the anterior pituitary to secrete ACTH, which in turn stimulates the adrenal cortex to secrete corticosteroids. Corticosteroids then feed back to inhibit the secretion of ACTH. Feedback mechanisms are important for the control of most hormones. For example, insulin (qv) secretion from the pancreas increases in response to increased blood glucose resulting from ingestion of a meal. Insulin increases tissue uptake and metaboHsm of glucose, which lowers blood glucose and in turn reduces insulin secretion. 

CeUs synthesize and secrete multiple hormones. Eor example, some ceUs in the anterior pituitary have the capacity to secrete both polypeptide hormones, ESH and LH. CeUs also can secrete different chemical classes of hormone, eg, ceUs in the adrenal meduUa synthesize and secrete the... 

Two fundamental questions have emerged from these studies, ie, to what extent are agonists and antagonists binding similarly or differendy to the respective receptors, and can inhibitory compounds be developed that are active in vivo in humans as well as in vitro. An oxytocia antagonist that can block premature uterine contractions presents a promising example of the clinical utihty of such stmctures (47). Both linear as well as bicycHc modifications of these hormones also have provided new antagonist stmctures. 

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