Chemical differences between bovine pineal antigonadotropin and arginine vasotocin

Studies were conducted in order to characterize chemically a partially purified antigonadotropic factor extracted from bovine pineal glands (PAG). Because several reports have appeared recently suggesting a role for arginine vasotocin (AVT) as a pineal antigonadotropin, our experiments were designed to determine the presence or absence of this nonapeptide in our material. A comparison of biologically active PAG and synthetic AVT revealed dissimilar UV absorption and fluorescence maxima, different mobilities on thin layer chromatography and paper electrophoresis, as well as different elution patterns on DEAE Sephadex ion-exchange chromatography. Amino acid analysis using 2 different methods revealed dissimilar amino acid compositions. On the basis of these and other chemical data, it is concluded that our preparations of PAG do not contain AVT.