The presence of a pepsin-like entity in the urine has been known for almost a century; Brücke 1 first mentioned it in 1861, Frouin 2 described it in 1904, and Gottlieb3 further added to its understanding in 1924. It remained dormant until 1946, when Farnsworth 4 published a review of the literature, with comments on the absence of this pepsinlike substance in the urine of perniciousanemia patients. The following year, Bucher 5 evaluated the effects of varied diets on this urinary substance, now termed "uropepsin," hereafter referred to as U-P (the end-product of uropepsinogen activation). The last decade has seen a renewed interest in U-P studies, further intensified by the impact of Selye's "Adaptation Syndrome" and the emergence of endocrinology from its early theoretical stage to the maturity of the corticotropin-cortisone era, and strengthened by innumerable practitioners who would spare their patients the discomforts of the stomach tube.
ROSENBERG SJ. Uropepsin ExcretionStudies in Three Hundred Patients. AMA Arch Intern Med. 1957;100(6):937–942. doi:10.1001/archinte.1957.00260120081009