Turkey Prolactin: Purification by Isotachophoresis and Partial Characterization

Preparative isotachophoresis (ITP) has been employed in the purification of prolactin from the pituitary gland of the domestic turkey. Prolactin was purified in relatively few steps and required only small quantities of pituitary tissue. The resultant highly purified hormone was recovered in substantially higher yield and with greater biological activity than was turkey prolactin purified by other techniques. Total yield of purified prolactin was 850 mg/kg of wet weight of pituitaries, but aggregation of prolactin into high molecular weight polymers during the purification process re-duced the yield of biologically active monomeric prolactin to 446 mg/kg. Turkey prolactin showed molecular polymorphism during purification and characterization. The hormone was isolated as two peaks from ITP, resolved into at least five bands on isoelectric focusing and disc electrophoresis, and exhibited two molecular forms on SDS electrophoresis. The chemical and biological characteristics of turkey prolactin isolated by ITP were similar, though not identical, to those of turkey and chicken prolactins purified by conventional techniques