Yosoji Ito

PAROTIN: A SALIVARY GLAND HORMONE

The endocrine function of the salivary glands has been under study in Japan for more than thirty years, ever since T. Ogata of the University of Tokyo started research on the experimental pathology of the salivary glands. During this time, I and my co-workers isolated an active principle, parotin, in pure crystalline form from the bovine parotid gland; we surmised that it was the salivary gland hormone, as Ogata and his associates claimed. Later this active substance was investigated closely by many workers of the consolidated research group;* not only was light thrown on its chemical nature, but it was established that this substance is able to compensate experimental animals and human beings for deficiencies in the parotid gland. Furthermore, my associates and I isolated active principles in the form of homogeneous proteins having biological activities similar to tho5e of parotin from bovine, porcine, and equine submaxillary glands (S-parotin), from human saliva (saliva parotin), and also from human urine (uroparotin) (FIGURE 1). This paper deals with the chemistry and biochemistry of parotin and the parotinlike substances described above.

A PAROTIN-LIKE SUBSTANCE (α-PAROTIN) IN BOVINE PAROTID GLAND III

An active parotin-like substance was obtained with acetone or ethanol fractionation procedure from bovine crude parotin and its recovery was almost 70%.In the alumina and XE-58 column chromatography of the reprecipitate at 50% acetone concentration in acetone fractionation, 2-2.5-fold activity (0.25-0.2mg/kg) and recovery of 50-70% were obtained but not homogeneous state.The reprecipitate at 50% acetone concentration was further purified with acrinol and ammonium sulfate.The purified substance having hypocalcemic activity at the dose of 0.1mg/kg, was obtained with a yield of 10-12mg/kg bovine parotid gland. The purified substance was almost homogeneous in electrophoretic and ultracentrifugal analyses.This purified parotin-like substance was named α-parotin.

Detoxication and excretion of radioactive strontium. II. Effect of several organic acids having chelating ability.

Effect of tricarballylate, citraconate, tartrate, lactate, and citrate, which are able to form chelating complex with strontium, on the distribution of parenterally administered radioactive strontium was examined, and it was indicated that all of these organic acids markedly decreased skeletal depostion of radiostrontium and four acids other than citrate markedly increased radiostrontium in the blood serum and soft tissues.