The antigonadotropic activity and amino acid composition of a total and dialyzed melatonin-free pineal extract

The antigonadotropic activity of a melatonin-free pineal extract before and after a 24 h dialysis was assessed by the mouse uterine-weight test. In both cases, the uterus-stimulating effect of HCG was inhibited, showing that after dialysis the extract not only retains its effect but that the latter is even higher. The amino acids content established by an amino acid analyzer was the same in two batches of extract obtained from two different stores of pineal powder. The analyzer also showed that the glutamic acid is the prevailing component as a free and bound amino acid in the total extract. It was also found that methionine is absent from the dialyzed extract. Qualitative analysis of the pineal extract revealed 16 amino acids and a concentration of proteins of 1.90-1.96 mg/ml. Quantitatively, the glutamic and aspartic acids, proline and glycine prevail over the other constituents. The glutamic acid concentration was over two times higher than the latter three.