Endocrine agents

Growth factors are paracrine or endocrine agents, peptides or proteins, released by one cell to regnlate proliferation in adjacent cells (chapter 12) (Table 21.4). Normal cell proliferation requires the presence of growth factors but proliferation of tumonr cells reqnires either no growth factors or much lower concentrations. There are several different characteristics of tumor cells that enable them to respond to very low concentrations of growth factors ... 

The remarkable efficacy of topical corticosteroids in the treatment of inflammatory dermatoses was noted soon after the introduction of hydrocortisone in 1952. Numerous analogs are now available that offer extensive choices of potencies, concentrations, and vehicles. The therapeutic effectiveness of topical corticosteroids is based primarily on their antiinflammatory activity. Definitive explanations of the effects of corticosteroids on endogenous mediators of inflammation await further experimental clarification. The antimitotic effects of corticosteroids on human epidermis may account for an additional mechanism of action in psoriasis and other dermatologic diseases associated with increased cell turnover. The general pharmacology of these endocrine agents is discussed in Chapter 39. 

Milne G.W.A. Ashgate Handbook of Endocrine Agents and Steroids, Ashgate Publishing Company, Brookfield. VT. 2000. 

Nicholson Rl, Hutcheson IR, Britton D, Knowlden JM, Jones HE, Harper ME, et al. Growth factor signaling networks in breast cancer and resistance to endocrine agents new therapeutic strategies. J. Steroid Biochem. Mol. Biol. 2005 93 257-262. 

TABLE 124—17. Endocrine Agents Commonly Used in Cancer Treatment... 

The US Environmental Protection Agency (EPA) Risk Assessment Foriim An endocrine disrupter is an exogenous agent that interferes with the synthesis, secretion, transport, binding, action, or elimination of natural... 

Type 2 diabetes is a heterogeneous and progressive endocrine disorder associated with insulin resistance (impaired insulin action) and defective function of the insulin-secreting (3-cells in the pancreatic islets of Langerhans. These endocrine disorders give rise to widespread metabolic disturbances epitomised by hyperglycaemia. The present classes of antidiabetic agents other than insulin act to either increase insulin secretion, improve insulin action, slow the rate of intestinal... 

Anthelmintic agents have been utilized to treat a multimde of nematode infections. These include roundworms, tapeworms, and lungworms in cattle and swine. Two classes of compounds included as anthelmintic agents will be discussed here, lev-amisole and thiabendazoles (thiabendazoles can also act as pesticides). Thiabendazoles can cause nephrotoxicity, teratogenesis, and immunosuppression and can disrupt endocrine balance. Because of these toxicides, residues of these compounds in food animals are of food safety concern. 

Until recently, there was little evidence that the response or survival benefit from one endocrine therapy was clearly superior to that achieved with other therapies. Given this equality in efficacy, the choice of a particular endocrine therapy was based primarily on toxicity (Table 86-8). Based on these criteria, tamoxifen is the preferred initial agent when metastases are present. An exception to this occurs when the patient is receiving adjuvant tamoxifen at the time or within 1 year of occurrence of metastatic disease. 

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