We have investigated the p-chlorophenylalanine-dependent loss of phenylalanine hydroxylase activity in cultured hepatoma cells. The similarity of the effect of p-chlorophenylalanine on phenylalanine hydroxylase in the hepatoma cells and that reported from studies in uiuo indicates that the loss of phenylalanine hydroxylase activity is due to a direct interaction of the amino acid analog-ue with...

We have investigated the p-chlorophenylalanine-dependent loss of phenylalanine hydroxylase activity in cultured hepatoma cells. The similarity of the effect of p-chlorophenylalanine on phenylalanine hydroxylase in the hepatoma cells and that reported from studies in vivo indicates that the loss of phenylalanine hydroxylase activity is due to a direct interaction of the amino acid analogue with ...

The mechanism by which p-chlorophenylalanine specifically reduces phenylalanine hydroxylase activity in rat liver in uiuo and in Reuber H4 hepatoma cells in culture has been investigated. Chromatography on hydroxylapatite of liver extract from rats injected with p-chlorophenylalanine showed that the compound differentially affected the three normal phenylalanine hydroxylase isoenzymes (I, II, a...

The mode of action of the p-chlorophenylalanine in these animals is not clear. pChlorophenylalanine, in vitro, is not an appreciable inhibitor of phenylalanine hydroxylase, and this is apparently so in vivo also as the lowering of phenylalanine hydroxylase activity shows a delayed response to p-chlorophenylalanine treatment. However, the decrease in phenylalanine hydroxylase activity is not cau...

The brain damage which occurs in untreated phenylketonuria probably results from the high plasma phenylalanine concentration prevailing in this condition, as treatment with a low-phenylalanine diet mitigates the situation. The actual cause of the brain damage is not known, but investigations have been carried out with high phenylalanine loads to simulate phenylketonuria and so elucidate the nat...

The present study was performed to examine the effect of tandospirone on sleep latency in a new insomnia animal model by placing rats on a grid suspended over water. For investigating the mechanism of tandospirone, the effect of tandospirone on sleep latency was also studied using rats that were depleted with neuronal serotonin (5-HT) after p-chlorophenylalanine administration. Tandospirone cau...