Preliminary results--isolation and identification of pineal neurohypophysial hormone-like activity

We have initiated a project designed to isolate and identify the neurohypophysial peptides found in the bovine pineal gland. Our principle interest is to provide definitive molecular evidence in order to eliminate the conflict created by the present literature as to the presence of arginine vasotocin in the mammalian pineal gland. The pineals were extracted and chromatographed according to standard methods for the isolation of neurohypophysial peptides. All fractions were assayed for their ability to cause milk ejection using the in vivo assay described by Hadley et al. (1975). However, during the course of the isolation procedure a partially purified fraction was isolated that showed neurohypophysial hormone-like activity. According to tests run on parallel chromatographic columns, the substance responsible for the neurohypophysial hormone-like activity could not be oxytocin, arginine vasotocin or arginine vasopressin.