The Role of 5-Hydroxyindoles in the Carcinoid Syndrome

Abstract

Publisher Summary This chapter assesses the role of 5-HT in carcinoidosis in the context of recent developments. The carcinoid syndrome is a model system to study the pharmacology of 5-HT in man; the symptoms and signs, apart from those of malignancy in general and tryptophan deficiency in particular, are all explicable in terms of one or other action of the amine. Bradykinin and lysyl bradykinin are of importance in carcinoid flush. Apart from direct evidence of their involvement, it is well recognized that there is no correlation between degree of flush and 5-hydroxyindole production; that patients may have a pronounced flush and yet put out a minimal excess of 5-HIAA. Carcinoid is most commonly derived from the gastrointestinal tract or related structures, including such unusual sites as thyroid, parotid, and biliary tract. Its origin from the female or male genital tract is well established. By far, the commonest location is the ovary. Histamine secretion and “geographical” flush in gastric carcinoid and the high intensity flush of bronchial carcinoid are discussed in the chapter. The chapter identifies those areas in this field of study where further experiment or observation is required.