The present invention provides stable metastin derivatives having excellent biological activities (a cancer metastasis suppressing activity, a cancer growth suppressing activity, a gonadotrophic hormone secretion stimulating activity, sex hormone secretion stimulating activity, etc.).By substituting the constituent amino acids of metastin with specific amino acids in the metastin derivative of the present invention, blood stability, solubility, etc. are more improved, gelation tendency is reduced, pharmacokinetics are also improved, and an excellent cancer metastasis suppressing activity or a cancer growth suppressing activity is exhibited. Furthermore, the metastin derivative of the present invention has the effects of suppressing gonadotropic hormone secretion, suppressing sex hormone secretion, etc.Ovaj pronalazak daje stabilne derivate metastina koji imaju odlične biološke aktivnosti (aktivnost suzbijanja metastaze kancera, aktivnost suzbijanja rasta kancera, aktivniost stimulacije izlučivanja gonadotropnog hormona, aktivniost stimulacije izlučivanja polnog hormona, itd.). Supstitucijom konstitutivnih aminokiselina metastina sa specifičnim aminokiselinama u derivatu iz ovog pronalaska, znatno se poboljšavaju stabilnost u krvi, rastvorljivost, itd., smanjuje tendencija ka geliranju, farmakokinetika se takođe poboljšava, a pokazuje se odlična aktivnost u suzbijanju metastaze kancera ili aktivnost u suzbijanju rasta kancera. Pored toga, derivat metastina iz ovog pronalaska pokazuje efekte u suzbijanju izlučivanja gonadotropnog hormona, u suzbijanju izlučivanja polnog hormona, itd.
