PGRMC1 and chronic kidney disease: CKD patients also demonstrated increased urinary excretion of plasma proteins and their fragments (e.g., A1AT, serum albumin, α-hemoglobin chain, and α-fibrinogen chain), kidney-specific proteins (uromodulin, gamma-chain Na+/K+-ATPase, and membrane-associated progesterone receptor component 1), and proteins excreted by the tubules, which may reflect chronic damage to the glomerular filtration barrier, increased glomerulosclerosis, and interstitial fibrosis.