Steroid hormones specific agents

The basic mechanism of steroid hormone action on target cells is similar for the various classes of agents. Differences in the actions of adrenocorticoids, estrogens, progestins, and androgens arise from the specificity of... 

Veterinary drugs are used to treat animals for bacterial infections (antibiotics) and parasitic infestations (anthelmintics, coccidiostats), to enhance growth (antibiotics, anabohcs, partitioning agents, thyrostats), to control fertility and reproduction (steroid hormones), or to alter behavior (tranquillizers and sedatives). Within each of the drug types there are different classes and methods for residue analysis are typically class specific (e.g., methods for the class of tetracycline antibiotics). In certain cases, mrdtiresidue methods are available that are broader than specific classes. 

So far Group B agents appear to specifically act on XDH, although studies of other enzymes may reveal additional effects. Group C contains representative steroid hormones which induce or suppress levels of XDH and in one case (hydrocortisone) induces an increase in tyrosine transaminase. Group D contains unsaturated fatty acids including oleic, linoleic and linolenic acids. These agents suppress levels of XDH and PNP. 

Photochemically reactive molecules have often been used as labels for specific sites in proteins and nucleic acids. Psoralen derivatives serve as relatively nonspecific photochemically activated crosslinking agents for DNA and double-stranded RNA.195 Aryl azides are converted by light to aryl nitrenes, which react in a variety of ways including insertion into C-H bonds (Eq. 23-27).200 201 In some cases UV irradiation can be used to join natural substrates to enzymes or hormones to receptors. For example, progesterone, testosterone, and other steroids have been used for direct photoaffinity labeling of their receptors.202 Synthetic benzophenones have also been used widely as photoactivated probes.203... 

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