Metabolic Clearance and Secretion Rates of Human Prolactin in Normal Subjects and in Patients with Chronic Renal Failure*

Abstract

Hyperprolactinemia (PRL, >15 ng/ml plasma)was observed in 70% of 73 patients with chronic renal failure (CRF) on maintenance hemodialysis. Plasma GH was also elevated (>5 ng/ml) in 42%, but PRL, GH, and creatinine levels did not correlate with one another. The MCR of human [131I]-PRL was determined in 6 normal females and 6 females with CRF using a constant infusion method. The PRL MCR was decreased by 33% in the CRF patients compared with that in normals (26.8 ± 2.3 vs. 40.2 ± 2.5 ml/min/m2; P < 0.01). The PRL secretion rate was 367 ±63 ng/min/m2 in the normals and 1162 ± 385 (P <0.05) in the CRF group. The disappearance of [131I]hPRL from plasma after discontinuation of the constantinfusion was multiexponential. The initial phase (0–45 min) disappearance rate was significantly prolonged (P < 0.01) in CRF patients. Sephadex G-75 gel filtration of plasma from a CRF patient obtained 30 min after a single injection of human [131I]PRL revealed that 94% of the immunoprecipitable radioactivity eluted in the po...