URINARY PROLACTIN EXCRETION IN MAN*

Abstract

PROLACTIN was the first pituitary hormone to be prepared in crystalline form (1), and various methods have been successfully used to extract it from pituitary tissue and to assay the material thus obtained. However, with one exception (2), no assay of prolactin excreted in human urine in terms of international units has been reported. The purpose of this paper is to present a method of extraction and assay of prolactin excreted in human urine, together with some of the results of assays in patients. Extraction procedure 1. Precipitation: To a 24-hour urine specimen, refrigerated during collection, are added 1 per cent by weight of sodium chloride and four volumes of 96 per cent ethyl alcohol. If the urine is not acid, it is acidified to litmus with acetic acid before addition of the alcohol. The precipitate is allowed to settle over night in the refrigerator, and collected by decantation and centrifugation. The precipitate is washed twice with 96 per cent alcohol, twice with ether, and dried. 2. Dialysis: After grinding, the precipitate is extracted with three 15-cc. volumes of distilled water, thirty minutes being allowed for each 15-cc. volume. The extract is dialyzed under refrigeration in a cellophane membrane against 6 hourly changes of 0.5 per cent sodium chloride. 3. Reprecipitation: The extract within the membrane is then treated as if it were an equivalent volume of urine, according to the method described in section 1. The final result is a dried precipitate.