RECENT PROGRESS IN THE STUDY OF ANALYTICAL METHODS, TOXICITY, METABOLISM AND HEALTH EFFECTS OF ORGANOTIN COMPOUNDS

Abstract

Over the years, a variety of uses has been found of organic tin compounds as fungicides, as stabilizers in plastics and for other industrial uses. The purpose of this article is to summarize and review the results so far obtained as to the analytical method for organotins in biological samples, the toxicity, metabolism, and biochemical and health effects of organotin compounds. 1) Many methods have been developed for analysis of organotin compounds by spectrophotometry, polarography, gas- or liquid-chromatography, etc. These methods, however, are mainly for analysis of organotins in standard solutions or in water, and are not suitable for organotin compounds in biological samples. Recently, we have developed several methods for analysis of various kinds of organotin compounds in biological samples. These methods are able simultaneously to separate and determine trace amounts (at nanogram order) of organotin compounds and their metabolites in the same biological samples. 2) Acute toxicity of organotin compounds which appeared on the literature are summarized. Trialkyl and triaryl compounds seem to be more toxic than the tetra-, di-, or mono-compounds of the same chain length. With an increase in the number of C atoms the toxicity of alkyl compounds decreases. Aryltin compounds are less toxic than alkyltin compounds. 3) Intestinal absorption sites for tetra-alkyltins are jejunum and duodenum, and those for trialkyltins are ileum and jejunum. A considerable amount of orally administered tetra- and trialkyltins of low molecular weights are absorbed, but only very little of the other organotin compounds seems to be absorbed from the gasterointestinal tract. Absorbed organotin compounds rapidly undergo dealkylation by the microsomal mono-oxygenase system dependent on cytochrome P-450 in the liver, brain or other organs, and the compounds and their metabolites distribute to the whole body, ultimately being excreted into urine, bile and faeces. The biological half life of organotin compounds in mammals is usually short, a half of the amount of tributyl- and triphenyl-tins deposited in the body disappearing in several days. A part of organotin compounds excreted into bile is demonstrated to have been absorbed from the intestine and to circulate in the body via enterohepatic circulation. 4) Specific effects of organotin compounds on the biological systems and health include disturbance of the structure and function of the central nervous system (interstitial edema of white matter), inhibited oxidative phosphorylation in mitochondria of cells, atrophy of the thymus and thymus dependent lymphoid tissues resulting in the dysfunction of T cells for immunity, inhibited enzyme activity, lesions in the liver and bile ducts etc., although some specificity is observed among species of animals and organotin compounds. Recently we found that a single oral administration of triphenyltin fluoride to rabbits induces transient diabetes and diabetic lipemia by inhibiting insulin secretion from morphologically normal pancreatic B-cells. Furthermore, the compound inhibits the aggregation of platelets in vivo and in vitro. 5) There are several reports on human organotin poisoning. The symptom indicates that organotin compounds affect mainly the central nervous system, producing cerebral edema. Other manifestations include irritation and inflammation of skin and mucous membrane, liver and bile duct dysfunction, keratitis, anosmia, etc. Health effects of organotin compounds are usually observed among workers exposed to the compounds and are the same as observed in experimental animals.