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A G Rico

Publications and source records attributed to A G Rico.

59 records · Page 4Linked to original sources
PubMedDate not supplied

Urine gamma-glutamyl transferase in rat kidney toxicology: nephropathy by repeated injections of mercuric chloride. Effects of sodium selenite.

Groups of 5 male and 4 female Cobs CD rats weighing 250--350 g were injected intraperitoneally, daily for 15 days, with 5 mumol HgCl2/kg, 5 mumol Na2SeO3/kg, or (5 mumol HgCl2 + 5 mumol Na2SeO3)/kg in a 10 ml/kg vol. of saline. Control animals were injected with saline only. Injection of saline or sodium selenite produced neither modification of diuresis, nor of urine elimination of sodium, potassium, chloride, phosphates, urea, creatinine and gamma-glutamyl transferase (GGT). Injection of mercuric chloride induced a massive increase of urine GGT, diuresis and phosphaturia and a decrease of kaliuria and natriuria. Those effects reflect a kidney tubular lesion which seems to be more severe in males than in females. Injection of mixed sodium selenite and mercuric chloride or separate injection of both compounds had similar effects. In both sexes, urine GGT elimination was delayed and about 2 times lower than with HgCl2 alone. In females, the other urine parameters were almost normal whereas in males, diuresis and phosphaturia were slightly increased and kaliuria decreased. The observation of urine GGT elimination attests, in vivo, that sodium selenite decreases tubular toxicity of mercuric chloride and resulting kidney function disturbances.

Animals↗
PubMedDate not supplied

[Carcinogenic potential of estrogens used in breeding].

The oestrogens that are used in husbandry are oestradiol (natural compound), zeranol (non-steroid drug) and stilbenes such as diethylstilboestrol (D.E.S.). Oestrogens present carcinogenic activity especially on target organs (cervix uteri, corpus uteri, breast). Oestrogens, except perhaps D.E.S., do not initiate cancer directly, but may influence carcinogenesis by their hormonal properties. In these conditions it is possible to define rules of use which can protect the health of consumers. It is necessary to take into account the no-hormonal effect level, and the metabolism after oral administration. Oestradiol and zeranol, when used in good husbandry practice are not toxic, but D.E.S. must be banned and controlled.

Animal Husbandry↗
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Toxicological significance of covalently-bound residues.

Bound residues may be defined in terms of the nonextractable radioactivity which persists in tissues after administration of radiolabelled compounds to an organism. This fraction is found to contain natural endogenous compounds resulting from incorporation of degradation products of the administered substance into intermediary metabolites (amino acids, carbohydrates etc.). However, 'new' compounds are also found which arise from covalent binding of the administered substance or its metabolites to endogenous macromolecules. The former fraction is nontoxic, but in the second case the nature of the covalent binding is important from the toxicological point of view. It is unspecific and irreversible, and often involves the action of short-lived and highly reactive intermediates. The covalent bond is usually thermodynamically irreversible. A good example is provided by bromobenzene, which binds to proteins via the 3,4-epoxide, which is the hepatotoxic agent. From the above considerations it is possible to distinguish two types of metabolites that may be found in foodstuffs prepared from drug-treated animals. The first are represented by the drug itself and its primary metabolites. These compounds are potentially more or less toxic to the consumer. The second type are the covalently bound metabolites. These have lost their reactivity in an irreversible manner and may be considered to have low toxicity to the consumer as well as low bioavailability. Some examples (trenbolone acetate, aflatoxin, carbaryl) are discussed to support this contention.

Animals↗
PubMedDate not supplied

[Toxic effects of methoxy-ethyl-mercury in the quail: influence of fasting].

Quails fed methoxy-ethyl-mercury-treated wheat (20 ppm of Hg) during 10 or 20 days, have been submitted to a three-day fasting following contamination. The test proved to be lethal for a number of intoxicated animals but not for controls. Mercury clearance was modified by anorexia; following fasting, there was a redistribution of the metal, with high concentrations in the liver and kidneys. According to the results of a blood survey uric acid, urea and T. G. O. levels appeared to be the most altered parameters. Transient high blood uric acid levels in intoxicated and anorectic animals could be attributed to kidney dysfunctioning. A possible effect of methoxy-ethyl-mercury on neoglycogenesis was discussed.

Animals↗