Pharmacokinetics of technetium-99m-MAG3 in humans.
Technetium-99m-mercaptoacetylglycylglycylglycine (99mTc-MAG3) is introduced to replace o-iodohippurate (OIH) for renal function studies. For interpretation of clinical findings, extensive pharmacokinetic studies were performed on patients. These showed that 99mTc-MAG3, compared with OIH, has a higher plasma-protein binding, an essentially higher intravascular concentration, a smaller volume of distribution and, with practically identical biologic half-lives, a correspondingly lower clearance. Simultaneous steady-state measurements resulted in a 1.5-fold higher clearance of OIH than of 99mTc-MAG3 (n = 124). Competitive inhibition of the tubular transport system by p-aminohippurate (PAH) (20 patients) revealed a distinctly higher suppression of the 99mTc-MAG3 clearance than of OIH which indicates a lower affinity of the 99mTc complex to the tubular cell. The plasma extraction efficiencies of both agents, measured during surgery (n = 5), did not indicate an extrarenal elimination of 99mTc-MAG3. This new radiopharmaceutical is a pragmatic alternative to OIH and offers advantages not only for scintigraphic imaging but is also suited for quantitative renal function studies.
Bubeck
B
B
Department of Nuclear Medicine, University of Heidelberg, West Germany.
Brandau
W
W
Weber
E
E
Kälble
T
T
Parekh
N
N
Georgi
P
P
D006801:Humans; D007465:Iodohippuric Acid / Q000493:pharmacokinetics; D007668:Kidney / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D007677:Kidney Function Tests; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology; D016030:Kidney Transplantation; D009842:Oligopeptides / Q000493:pharmacokinetics*; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics*; D011877:Radionuclide Imaging; D017263:Technetium Tc 99m Mertiatide; D010130:p-Aminohippuric Acid / Q000494:pharmacology
D009842:Oligopeptides; D015609:Organotechnetium Compounds; D007465:Iodohippuric Acid; D017263:Technetium Tc 99m Mertiatide; D010130:p-Aminohippuric Acid