A. Heringová

β-glucuronidase activity in the liver of infant mammals

Niedrige Leber-β-Glucuronidase (Phenolphthaleinglucuronid-Substrat) neugeborener Ratten steigt in der dritten Woche auf Erwachsenenwerte. Die Aktivität sinkt bei Meerschweinchen von der Geburt an, steigt bei Kaninchen zwischen Geburt und drittem Lebenstag und zeigt bei Mäusen während der postnatalen Entwicklung geringe Schwankungen.

β-Glucuronidase Activity in the Serum of Infants

Glucuronide metabolism has received much attention because of its relationship to neonatal jaundice [l, 2, 3, 41. The development of hepatic conjugation mechanisms has been extensively studied [l, 21 but the development of /?-glucuronidase activity has been followed in the liver of mice only [5]. It has been reported [5] that B-glucuronidase activity is significantly higher in newborn and infant mammals than in adults. I n previous work it has been shown that in the rat [6], mouse and rabbit [7] ileum there is a rise in /?glucuronidase activity after birth (using phenolphthaleinglucuronide as the substrate) and a fall after weaning. Later it was found [8] that liver @-glucuronidase activity (phenolphthaleinglucuronide served as the substrate) in newborn rats was significantly lower than in adult animals, in rabbits values increased up to day 3 and in mice only small developmental changes were found. This was in contrast to the finding of Karunairatnam et al. [5] who used phenylglucuronide as the substrate, and it was concluded [8] that the opinion voiced repeatedly in the literature that infant animals tend to have a higher /3-glucuronidase activity in the liver applies to mice only and only if phenylglucuronide is used as the substrate. These findings and the preliminary report of Dutton et al. [9] indicated that glucuronide synthesis could be high in some species during the neonatal period and not low as has been judged earlier [cf. 1, 2, 3, 4, 91 and led us to study the postnatal changes of B-glucuronidase activity in infants. This report describes results of estimation of /3-glucuronidase activity in serum.