Glucuronyl transferase activity

Bl. Bakken, A. F., Effects of unconjugated bilirubin on bilirubin-UDP-glucuronyl transferase activity in liver of newborn rats. Pediat. Res. 3, 205-209 (1969). 

B17. Black, M., Billing, B. H., and Heirwegh, K. P. M., Determination of bilirubin UDP-glucuronyl transferase activity in needle-biopsy specimens of human liver. Clin. Chim. Ada 29, 27-35 (1970). 

M5 Menken, M., Barrett, P. V. D., and Berlin, N. I., Assay of hepatic glucuronyl transferase activity using ( C) bilirubin as substrate. Clin. Chim. Acta 14, 777-785 (1966). 

Deliconstantinos G, Mykoniatis M, Papadimitriou D. 1986. Carbon tetrachloride modulates the rat hepatic microsomal UDP-glucuronyl transferase activity and membrane fluidity. Experientia 42 181-183. 

Commercially available black pepper comes from the entire unripe fruit of a Piper nigrum L. plant and is valued for its pungent taste and aroma. Besides its hot flavor, there are many folk medicine remedies using black pepper. It has antiallergic activity. Piperine strongly inhibits hepatic arylhydrocarbonhydroxylase and UDP-glucuronyl transferase activities. Some proven uses for black pepper extracts are as an insecticide and as a tumor inhibitor. To research claims such as these, it is necessary to isolate the components of pepper. 

Indinavir has been compared with abacavir in a randomized equivalence trial in 562 patients who were also taking lamivudine and zidovudine (10). The only significant difference in adverse effects was that there was hyperbilirubinemia in 8% of those taking indinavir and 2% of those taking abacavir. It has been postulated that indinavir-induced hyperbilirubinemia is due to inhibition of bilirubin UDP glucuronyl transferase activity, since it is more common in individuals with Gilbert s syndrome (11). 

Inhibition of glucuronyl transferase activity by indinavir has been blamed for an interaction of indinavir with levothyroxine, causing hyperthyroidism (43). 

As adult cats have a relative deficiency in hepatic microsomal glucuronyl transferase activity, glucuronide conjugates of drugs and endogenous substances (such as bilirubin and steroidal substances) are slowly synthesized in... 

By the mid-1960s the problem of administering inappropriate drug doses to pediatric patients had been clearly documented. In 1959 reports of the gray baby syndrome in neonates were published documenting the toxicity of chloramphenicol when adult doses were miniaturized to infants without consideration of maturation differences. The resulting deaths occurred because neonates have immature glucuronyl transferase activity necessary for the biotransformation of chloramphenicol and therefore accumulation occurred. When chloramphenicol... 

Glucuronyl transferase appears in the serum in patients with hepatic necrosis. Thus, even when the liver transferase level is depressed, the serum enzyme can still conjugate bilirubin in vitro. In such cases it is possible that the activity of the blood enzyme is the source of conjugated bilirubin found in the serum in patients suffering from hepatic necrosis associated with impaired hepatic glucuronyl transferase activity. 

Rats (a) Lower aryl hydroxylase and UDP-glucuronyl transferase activities, prolonged hexobarbital sleeping time in piperine-treated rats [8]... 

The UDP-o-glucuronate glycosaminoglycan jS-D-glucuronyl-transferase activity from the media and intima of pig aorta has been determined by the incorporation of D-[ C]gIucuronic acid into hyaluronic acid and heparan sulphate. ... 

The elaboration of androgen in male rats triggers an increase in microsomal enzyme activity which can be abolished or prevented by castration. However, it should not be inferred that all hepatic microsomal enzymes reach their peak activities concomitant with sexual maturation. Indeed, glucuronyl transferase activity toward p-nitrophenol is maximal in new-bom rats and tends to decline thereafter whereas transferase activi towards bilirubin or phenolphthalein is very low at birth and progressively increases to adult levels. Similarly, NADPH and cytochrome P-4S0-dependent microsomal enzymes have developmental patterns unrelated to each other and to cytochrome P-4S0. For example, aniline hydroxylase in male rats reaches peak activity at 2 weeks of age which is 2 4 weeks prior to sexual maturation, whereas ethylmorphine N-demethylase activity does not become maximal until about 4 5 weeks of age. During the first S weeks of life, these activities increase by about 100% but cytochrome P-4S0 changes only insignificantly. 

The fact that jaundice was noticeably absent in adolescents treated in a prophylactic manner with isoniazid, despite the occurrence of abnormal SGPT values, prompted Cohen and McNamara to investigate the effects of isoniazid on bilirubin metabolism (3 ) using rats as an experimental model. They found that hepatic bilirubin glucuronyl-transferase activity was enhanced in the animals receiving the drug. Such enhanced activity could account for the absence of hyperbilirubinaemia in subjects with biochemical evidence of hepatic dysfunction whilst receiving isoniazid. 

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