Extraction of pineal and uterine tissue at different pH values: a preliminary report on the occurrence of a few groups of compounds in both tissues.

Extraction of pineal glands has been performed at different pH values. After extraction at pH +/- 4.9, 'porphyrin'-containing protein did not occur in the extracts, while at pH +/- 6.3 these proteins had passed over partly into the extract; at pH +/- 6.8 the proteins could no longer be detected in the residues, but a partial breakdown had taken place. The activity of pineal extracts depends on the method of extraction. In the watery extracts (pH +/- 6.3) both of pineal and of uterine tissue the presence could be shown among others of: porphyrins bound to protein, the indole compound 'bufotenine' also bound to protein, 'kynurenine', a 'basic peptide' containing amines and 'flavoproteins'. The hypothesis is proposed that in uterine endometrium, tryptophan can be metabolized in at least two pathways, one leading to kynurenine and one to bufotenine. Formation of bufotenine, probably a physiologically important compound, might be influenced by the oestrous cycle and conversely.