Isolation and structure elucidation of bovine pineal arginine vasopressin: arginine vasotocin not identified

A large number of reports have demonstrated the presence of neurohypophysial hormone‐like peptides in mammalian pineal glands and an antigonadotropic function has been ascribed to pineal arginine vasotocin (AVT). We have undertaken large scale purification of bovine pineal neurohypophysial hormone‐like substances which demonstrate mouse mammary milk‐ejection activity (ME‐activity) in vitro. Peptides with ME‐activity were extracted from more than 5 kg of bovine pineal glands. ME‐activity containing peptides were found in both high (M_r∼ 10 000–15 000) and low (M_r∼ 500–1000) M_r species from Sephadex G‐25 chromatography of 0.2 n acetic acid extracts. After ultrafiltration in 5% formic acid, the neurohypophysial hormone‐like peptides were localized to an ultrafiltration M_r 500–1000 retentate. A homogeneous peptide, which shared an identical retention time (RT) and amino acid sequence with synthetic 8‐arginine vasopressin (AVP), was isolated by serial semipreparative high performance liquid chromatography. On the other hand, the non‐mammalian nonapeptide AVT was not identified.