Some observations on gonadotropin inhibitor (anti-LH) for human urine--with discussion on its possible source of origin.

Physicochemical characteristics of an anti-LH substance, partially purified from human urine, has been determined. It is an acid-precipitable, sialic acid containing glycoprotein with a molecular weight of 162,000. This substance on mg to mg basis has a 50 fold biological potency when compared to that of the crude gonadotropin inhibiting material. Dialysed human pineal protein extracts also showed anti-LH activity which was not attributed to sialidase activity. Polyacrylamide gel electrophoresis of such pineal extracts revealed a glycoprotein component with the same mobility as that of the urinary anti-LH protein. These observations suggest a possibility that the human pineal gland may be associated either with secretion or storage of this gonadotropin inhibiting entity.