NEW MATERIAL:A compound having the peptide sequence expressed by the formula. USE:A growth promoter for fishes. PREPARATION:For example, an mRNA is extracted from an eel pituitary gland body, and a cDNA complementary thereto is synthesized to clone an eel growth hormone gene with a DNA prove corresponding to the amino acid sequence near the N-terminal of the eel growth hormone. The above-mentioned cDNA is then integrated into a vector using a restriction enzyme and DNA polymerase, etc., and the resultant recombinant plasmid is used to transform a microorganism e.g. Escherichia coli. The resultant transformed microorganism is then cultivated in a nutrient culture medium to accumulate a growth hormone polypeptide for fishes in the culture. The formed polypeptide is then collected from the culture to afford the aimed compound expressed by the formula.
