Chromatographic Evidence for Vasotocin Biosynthesis by Cultured Pineal Ependymal Cells from Rat Fetuses

Abstract

Cultured pineal ependymal cells from rat fetuses 17-19 days post-coitum released into their media a substance that had hydroosmotic, antidiuretic and rat uterine activities. Paper chromatography on concentrates from culture media demonstrated that the substance possessing all the above activities was eluted from a slow moving region (Rf 0.15-0.35) with a peak at 0.20-0.30. This region was not significantly different from the Rf of synthetic arginine vasotocin (AVT) used as standard. Neither hydroosmotic nor rat uterine activities were detected in the chromatographic eluates from the fast moving region corresponding to the Rf of synthetic oxytocin (0.55-0.65) used as standard. The chromatographic mobility of biologically active molecules from culture media, the ratio of the activities and their susceptibility to tryptic digestion, demonstrated the presence of a basic peptide indistinguishable from synthetic AVT. The total amount of AVT released into the medium during 43 days of incubation is about 40 times greater than the amount contained in non-incubated pineal glands of the same age, strongly suggesting de novo synthesis of AVT.