Drug-induced porphyrin biosynthesis--XVIII. Effect of modulation of intracellular cyclic AMP levels on drug-induced porphyrin biosynthesis in chick embryo liver cells maintained in serum-free medium

Serine and glycine-induced catalepsy in porphyric rats: an animal model for psychosis?

It was investigated whether an increased demand for glycine, as postulated to occur in patients who have suffered from episodic psychoses accompanied by multiple perceptual distortions, could evoke psychotic reactions. Catalepsy was used as a measure for psychosis and was observed after injection of serine or glycine in porphyric rats. Catalepsy was was shown to occur after serine as well as glycine administration in 2-allyl-2-isopropylacetamide (AIA) pretreated rats, while in lead (Pb) + phenobarbital pretreated rats only glycine was effective. Administration of AIA to rats resulted in a strongly enhanced excretion of porphobilinogen (PBG) in urine, while Pb + phenobarbital pretreated rats showed increased excretion of delta-aminolevulinic acid (delta-ALA). The Pb + phenobarbital pretreated animals showed elevated serine plasma levels and lowered glycine plasma levels 18 hours after injection, while no significant differences in plasma levels of these amino acids were found 24 hours after AIA administration. In AIA or saline pretreated animals, but not in those pretreated with Pb + phenobarbital, glycine formation from serine was elevated. It is concluded that the present animal model can be used to investigate episodic psychoses.