Bioactivities of nerve growth factor from Chinese cobra venom.

The nerve growth factor, NGF, from Chinese cobra Naja naja atra venom was isolated by gel-filtration and ion-exchange chromatography. Cobra NGF was characterized by analytical HPLC techniques as well as SDS-PAGE, and was proven to be a glycoprotein with a mol. wt. of 23 (+/- 2) kD and a pI of 9.2. The amino acid analysis and N-terminal sequencing were performed using conventional methods. Bioassays with cultured chick embryos ganglia and rat pheochromocytoma PC-12 cells revealed a promotion of fiber outgrowth, which is typical of NGF activity. Absence of enzymatic, toxicological, and teratogenic activities were shown by quality inspection. Since 1994, many clinical cases about volunteers receiving NGF treatment have been reported in mainland China. Bioactivities of NGF deal with a wide range of disciplines and technologies. In this paper we will discuss neuronal and non-neuronal effects of NGF treatment. Does the NGF cross the blood-brain barrier by transcytosis into the brain tissue? How is NGF important in wound healing, especially in peripheral nerve injury and diabetic neuritis? NGF may also be useful for male volunteers suffering from sterility, because it is possible that the sexual cells of testis can be promoted to maturity.