The biliary excretion of tartrazine. Sex differences in the rat and species differences in the rat, guinea-pig and rabbit

The excretion of tartrazine in the bile and urine has been studied in biliary cannulated rats, rabbits and guinea-pigs. This dye is excreted unchanged by these species. In the rat a sex difference in the relative amounts of tartrazine excreted in bile and urine has been found. Male rats excrete in 3 h about 17 % of an intravenous dose (50 μmol/kg) in the bile and about 70% in the urine, whereas females excrete about 40 and 45 % respectively. The biliary excretion of tartrazine in the rat appears to be influenced by dose level, for at the lower level of 4.5 μmol/kg male rats excrete about 9 % of an intravenous dose in the bile and 64% in the urine in 3 h, the corresponding values for female rats being 30% and 50%. There is also a species difference in the extent of biliary excretion of tartrazine (50 μmol/kg intravenously). The female rat and female guinea-pig excrete in 3 h about 40 % of the dose in the bile and a similar amount in the urine whereas the female rabbit excretes only 6% in the bile and nearly 70% in the urine. Previous work in this laboratory has shown that molecular weight is an important factor in the biliary excretion of foreign compounds and the present results fit in with this view.

The fate of benzoic acid in various species

1. The urinary excretion of orally administered [(14)C]benzoic acid in man and 20 other species of animal was examined. 2. At a dose of 50mg/kg, benzoic acid was excreted by the rodents (rat, mouse, guinea pig, golden hamster, steppe lemming and gerbil), the rabbit, the cat and the capuchin monkey almost entirely as hippuric acid (95-100% of 24h excretion). 3. In man at a dose of 1mg/kg and the rhesus monkey at 20mg/kg benzoic acid was excreted entirely as hippuric acid. 4. At 50mg/kg benzoic acid was excreted as hippuric acid to the extent of about 80% of the 24h excretion in the squirrel monkey, pig, dog, ferret, hedgehog and pigeon, the other 20% being found as benzoyl glucuronide and benzoic acid, the latter possibly arising by decomposition of the former. 5. On increasing the dose of benzoic acid to 200mg/kg in the ferret, the proportion of benzoyl glucuronide excreted increased and that of hippuric acid decreased. This did not occur in the rabbit, which excreted 200mg/kg almost entirely as hippuric acid. It appears that the hedgehog and ferret are like the dog in respect to their metabolism of benzoic acid. 6. The Indian fruit bat produced only traces of hippuric acid and possibly has a defect in the glycine conjugation of benzoic acid. The main metabolite in this animal (dose 50mg/kg) was benzoyl glucuronide. 7. The chicken, side-necked turtle and gecko converted benzoic acid mainly into ornithuric acid, but all three species also excreted smaller amounts of hippuric acid.

The metabolic fate of amphetamine in man and other species

1. The fate of [(14)C]amphetamine in man, rhesus monkey, greyhound, rat, rabbit, mouse and guinea pig has been studied. 2. In three men receiving orally 5mg each (about 0.07mg/kg), about 90% of the (14)C was excreted in the urine in 3-4 days. About 60-65% of the (14)C was excreted in 1 day, 30% as unchanged drug, 21% as total benzoic acid and 3% as 4-hydroxyamphetamine. 3. In two rhesus monkeys (dose 0.66mg/kg), the metabolites excreted in 24h were similar to those in man except that there was little 4-hydroxyamphetamine. 4. In greyhounds receiving 5mg/kg intraperitoneally the metabolites were similar in amount to those in man. 5. Rabbits receiving 10mg/kg orally differed from all other species. They excreted little unchanged amphetamine (4% of dose) and 4-hydroxyamphetamine (6%). They excreted in 24h mainly benzoic acid (total 25%), an acid-labile precursor of 1-phenylpropan-2-one (benzyl methyl ketone) (22%) and conjugated 1-phenylpropan-2-ol (benzylmethylcarbinol) (7%). 6. Rats receiving 10mg/kg orally also differed from other species. The main metabolite (60% of dose) was conjugated 4-hydroxyamphetamine. Minor metabolites were amphetamine (13%), N-acetylamphetamine (2%), norephedrine (0.3%) and 4-hydroxynorephedrine (0.3%). 7. The guinea pig receiving 5mg/kg excreted only benzoic acid and its conjugates (62%) and amphetamine (22%). 8. The mouse receiving 10mg/kg excreted amphetamine (33%), 4-hydroxyamphetamine (14%) and benzoic acid and its conjugates (31%). 9. Experiments on the precursor of 1-phenylpropan-2-one occurring in rabbit urine suggest that it might be the enol sulphate of the ketone. A very small amount of the ketone (1-3%) was also found in human and greyhound urine after acid hydrolysis.

Incorporation of 8-azaguanine and guanine by Cladosporium resinae

With (14)C-tagged 8-azaguanine and guanine in a Bushnell-Haas medium with glucose as a carbon source, the rate of incorporation of the two bases was determined in Cladosporium resinae. There was a marked preference for the incorporation of 8-azaguanine over guanine.

The fate of [14C] thalidomide in the pregnant hamster

The embryotoxicity and fate of [14C]thalidomide in the pregnant European golden hamster have been investigated. Daily administration of thalidomide (1 or 2 g/kg orally) to pregnant hamsters on days 4–12 inclusive of pregnancy was not embryotoxic. [14C]Thalidomide (150 mg/kg) administered on the 204th hr of pregnancy is well absorbed and about 84% of the 14C is excreted in the urine and 9% in the faeces in the 3 days after dosing. The urinary 14C consists of thalidomide (3% of dose), α-(o-carboxybenzamido)glutarimide (26%), 2- and 4-phthalimidoglutaramic acids (8%), 2-phthalimidoglutaric acid (0.2%) and 2- and 4-(o-carboxybenzamido)-glutaramic acids plus 2-(o-carboxybenzamido)glutaric acid (27%). 14C is present in the embryo and the relative concentrations of radioactivity in the embryo and plasma are about the same at 4, 12 and 24 hr after dosing. At 4 hr after dosing the embryo contains mainly thalidomide, but at 12 hr this has largely disappeared and the 14C consists of seven hydrolysis products. The lack of embryotoxicity of thalidomide in the hamster is thus not due to an inability of the teratogen to penetrate to the conceptus.

The fate of[14C]thalidomide in the pregnant rabbit

1. The fate of [(14)C]thalidomide orally administered to pregnant rabbits at the beginning of the sensitive phase of pregnancy has been studied. 2. After the oral administration of [(14)C]thalidomide on the 192nd hour of pregnancy about 68% of the radioactivity appears in the urine and 22% in the faeces. 3. The urinary (14)C is made up as follows (% of dose): thalidomide (2); alpha-(o-carboxybenzamido)glutarimide (16); 2- and 4-phthalimidoglutaramic acids (11); 2-phthalimidoglutaric acid (0.2); 2- and 4-(o-carboxybenzamido)glutaramic acids and 2-(o-carboxybenzamido)-glutaric acid (29). 4. The plasma (14)C concentration is maximal at 12hr. after dosing and the radioactivity persists for more than 58hr. At 4hr. the main compound in the plasma is thalidomide, but its concentration steadily declines while the concentration of its hydrolysis products increases. 5. At 12, 24 and 58hr. after dosing radioactivity is present in the embryo and the maternal tissues examined. The (14)C concentration in the embryo is at nearly all times higher than that in the plasma, brain, skeletal muscle and fat but lower than that in the liver and kidney. 6. At 4hr. after dosing the mother on the tenth day of pregnancy the specific activities of the embryo and the yolk-sac fluid are similar. 7. Thalidomide is found in the embryo together with seven of its hydrolysis products for more than 24hr. after dosing. The accumulation of radioactivity in the embryo is due to retention of the polar hydrolysis products.

The fate of the hydrolysis products of thalidomide in the pregnant rabbit

1. The fate in the pregnant New Zealand White rabbit of oral doses of four (14)C-labelled hydrolysis products of thalidomide, namely alpha-(o-carboxybenzamido)-glutarimide, 2-phthalimidoglutaramic acid, 2-phthalimidoglutaric acid and 2-(o-carboxybenzamido)glutaramic acid, administered on the 192nd hour of pregnancy has been studied. 2. About 60-95% of the administered (14)C of each compound appears in the urine in 58hr. and the remainder is found in the faeces and in the gut and its contents. 3. Radioactivity is present in the plasma, liver, kidney, brain, muscle, fat and embryo. 4. The (14)C-labelled substances in the plasma and embryo consist of the unchanged compounds and their further hydrolysis products. 5. Since the above four thalidomide hydrolysis products are found in the rabbit conceptus together with their further hydrolysis products after their oral administration to the pregnant rabbit, it appears that the teratogenic activity of thalidomide is due to the compound itself rather than to one or more of its hydrolysis products.

Independent effects of error magnification and field of view on compensatory tracking performance

This experiment evaluated the independent effects of error magnification and field of view on compensatory tracking performance. Both display and optical magnification were investigated. In general, the results demonstrated that: (1) the facilitative effect on performance of display magnification was primarily due to the concomitant field of view reduction and not magnification per se; (2) optical magnification facilitated performance but subsequent display gain increases had no further affect; (3) regardless of visual mode employed, optimum performance levels on a complex trajectory converged at approximately the same field of view. In was suggested that increasing the optical gain or decreasing the field of view resulted in subjects reducing their reaction times to target movements. No evidence was found which indicated that magnification facilitated visual perception.

Effects of display magnification, proprio- ceptive cues, control dynamics and trajectory characteristics on compensatory tracking performance

An experiment was performed on the NOTS-UCLA heavy inertia tracking simulator to assess effects of display magnification, proprioceptive cues, displacement aiding, trajectory characteristics and trajectory direction on tracking performance. Particular attention was paid to interactions among these variables. The results showed that: (1) 5x magnification significantly decreased tracking error compared to tracking without magnification; (2) proprioceptive cues related to both azimuth and elevation significantly improved performance; (3) velocity plus displacement-aiding control dynamics (time constant = 0.1 sec) produced significantly lower error scores than unaided velocity control dynamics (time constant = 0.0 sec); (4) since no crossover tendencies were found, the effects of the varables appear to be independent.