Endocrine disruptor occur from low-dose exposure to exogenous hormones or hormonally active chemicals such as bisphenol A. These chemical can bind to receptors for other hormonally mediated processes. Furthermore, since endogenous hormones are already present in the body in biologically active concentrations, additional exposure to relatively small amounts of exogenous hormonally active substances can disrupt the proper functioning of the body's endocrine system. Thus, an endocrine disruptor can elicit adverse effects at much lower doses than a toxicity, acting through a different mechanism. The timing of exposure is also critical. Most critical stages of development occur in utero, where the fertilized egg
Multiple endocrine neoplasia all but abandoned in the medical literature. Another early report was Schimke "et al." in 1968. OMIM also includes a fourth form of multiple endocrine neoplasia ("MEN4"), associated with CDKN1B. The presentation is believed to overlap that of MEN1 and MEN2. The "MEN1" gene consists of ten exons, spanning about 10 kb, and encodes a 610 amino acid protein named menin. The first exon and the last part of exon 10 are not translated. A main transcript of 2.8 kb has been described in a large variety of human tissues (pancreas, thymus, adrenal glands, thyroid, testis, leukocytes, heart, brain, lung,