Hormones definition

While these hormones definitely have their place, they effectively acidify your body if they are chronically secreted by your glands. In addition, because chronic stress causes us to either breathe faster (not deeper) or hold our breath, we are prone to more acidity. That s because our oxygen intake drops, and oxygen alkalizes our blood, as well as all of the tissues and organs the blood nourishes. 

However, the "action at a distance" can not be regarded as a prerequisite of plant hormone definition as long... 

It was agreed at the workshop that endocrine disrupting activity could only be adequately defined in terms of effects in intact animals, be they juvenile or adult, or in the offspring of exposed parents. For many chemicals, evidence of endocrine disrupting activity has been obtained only by the use of in vitro models, such as hormone binding assays. It was accepted, therefore, that chemicals active in such models should be considered only as potential EDs and should be distinguished from those established as active in vivo. For such chemicals, an alternative definition was recommended ... 

Lipids are naturally occurring organic molecules that have limited solubility in water and can be isolated from organisms by extraction with nonpolar organic solvents. Fats, oils, waxes, many vitamins and hormones, and most nonprotein cell-meznbrane components are examples. Note that this definition differs from the sort used for carbohydrates and proteins in that lipids are defined by a physical property (solubility) rather than by structure. Of the many kinds of lipids, we ll be concerned in this chapter only with a few triacvlglycerols, eicosanoids, terpenoids, and steroids. 

An important observation linking Ca + to hormone action involved the definition of the intracellular targets of Ca action. The discovery of a Ca -dependent regulator of phosphodiesterase activity provided the basis for a broad understanding of how Ca and cAMP interact within cells. 

Much of the early work with certified reference materials was linked to the derivation of reference methods and there was a period in which primary or definitive (i.e. very accurate but usually very complex) and secondary (or usable) methods were reported e.g. steroid hormones (Siekmann 1979), creatinine (Siekmann 1985), urea (Welch et al. 1984) and nickel (Brown et al. 1981). Although there are some application areas, such as checking the concentrations of preparations listed in a pharmacopoeia, where a prescribed, defined method has to be used, in practice such work is limited. However, this approach to chemical analysis is no longer widely used and will not be further discussed. The emphasis now is placed on using RMs to demonstrate that a method in use meets analytical criteria or targets deemed to be appropriate for the application and to develop figures of merit (Delves 1984). 

SlEKMANN L (1979) Determination of steroid hormones by the use of isotope dilution mass spectrometry a definitive method in clinical chemistry. J Steroid Biochem 11 117-123. 

Microorganisms at the rhizosphere are known to produce plant growth regulators using precursors released by the roots (71), which can influence root morphology (3) the degradation of these hormone-like substances could be prevented by their incorporation into humic molecules, which would preserve their chemical properties. However, definite proof is still lacking recent studies have shown the... 

Stable in acidic, neutral and basic aqueous solutions Pale yellowish solid, faint characteristic odor Flash point 119°C (Pensky-Martens closed tester) Pyriproxyfen is an insect growth regulator which acts both as an ovacide and as an inhibitor of development (juvenile hormone mimic) against white flies, scale, and psylla. The specificity of pyriproxyfen, and its low mammalian toxicity, allow for some variation in application timing. For example, the lack of toxicity to bees allows pyriproxyfen to be applied during bloom on apple trees, and its low mammalian toxicity allows for a very short pre-harvest interval on citrus The residue definition is for pyriproxyfen alone... 

J. Chayen, Cytochemical bioassay and its potential place in compendial definitions A method that offers sensitivity as well as specificity, in Hormone Drugs, U.S. Pharmacopeial Convention, Rockville, MD, 1982, pp. 48-58. 

Many aspects relating to the specificity and intensity of gene transcription in response to hormones remain open. Nevertheless, a prudent conclusion permits establishing that two definite elements are intervening the interaction of the receptor dimer with the palindrome and several protein-protein interactions that are produced between the dimer and the remaining components of the transcription machinery (Beato 1989). 

The quantitation of a protein that has a specific biological function, a hormone, for instance, may not give a true indication of its biological activity owing to the inactivation of some of the protein. For proteins that have definite biological functions the choice is between chemical quantitation and bioassays. For this reason the catalytic activity of an enzyme is more frequently measured than is its protein concentration. 

By definition all hormones affect the behavior of their target cells. Examples of the interplay between endocrine disturbances and their biochemical consequences are provided by some of the diseases of the thyroid, which directly affects basal metabolic rate, and diabetes mellitus, where glucose metabolism is deranged. 

Both hypo- and hyperparathyroidism have been observed in human beings, and, if the principle of genetic gradients (p. 13) is valid, various intermediate levels of hormone activity will be found in the general population. Although the data on the subject, with the exception of that concerning anatomy, are not definitive, there would seem to be little doubt as to the existence of several-fold variation in the parathyroid activities of "normal" individuals. 

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