Abstract
The intestinal absorption of tilactase (containing 6.7% β-galactosidase, 10, 000 ONPG unit/g) was studied following oral administration to rats of different age(1-, 7-, 14-, 17-, 21- and 49-days old). Concentrations of β-galactosidase in plasma, tissues and other body fluids were detected by radioimmunoassay(RIA) and/or o-Nitrophenyl-β-D-gactopyranoside (ONPG) methods.
1. After oral administration of tilactase at a dose of 4g/kg (β-galactosidase : 268mg/kg) to 49-days old rats, β-galactosidase was not detected in the plasma, liver and urine.
2. After oral administration of tilactase at a dose of 0.04 and 0.4g/kg to 7-days old rats, traces of β-galactosidase were detected in the liver.
3. After oral administration of tilactase at a dose of 4g/kg to 7-days old rats, the absorption of β-galactosidase from small intestine was observed with an estimated absorption ratio of 0.2%.
4. After intravenous injection of β-galactosidase (1.15mg/kg) to 7-days old rats, high level was especially observed in the liver and spleen. In the case of high dose (β-galactosidase 11.5mg/kg), hepatic uptake was saturated.
5. β-galactosidase-like immunoreactive substance, which was absorbed from small intestine of 7-days old rats, was found to have similar enzymatic activity and molecular size as that of administered β-galactosidase.
6. After intravenous injection to 7-days old rats, β-galactosidase was not excreted into bile and urine.
7. After intravenous injection of 125I-β-galactosidase, a low molecular weight degradation products were observed in plasma as revealed by gel filtration radio-chromatography.
