[Plasma amino acid disturbances and depression]

Plasmatic amino acids concentrations were measured in 59 depressive patients and compared with that of a control population. Serine, glutamine, cystine, lysine and arginine have increased levels in the depressed males and females; so are 3 competitors of the tryptophan for the transport through the blood-brain barrier: valine, leucine and isoleucine. The tryptophan ratio is decreased in the depressive males. The sum of the competitors of the tryptophan is increased in the depressive males and females. All these results are discussed in relation with an abnormality of the carrier through the blood-brain barrier in the depressive state, without no proof thereof being however given.