Effect of gentamicin on renal function in the rat

Area of Science:

• Nephrology
• Pharmacology
• Toxicology

Background:

• Gentamicin is an antibiotic known to cause kidney damage (nephrotoxicity).
• Understanding the early functional changes in the kidney due to gentamicin is crucial for preventing toxicity.

Purpose of the Study:

• To investigate the early functional alterations in rat kidneys following gentamicin administration.
• To identify specific transport systems affected by gentamicin that may correlate with nephrotoxicity.

Main Methods:

• Rats were injected daily with gentamicin (100 mg/kg) for 1 to 6 days.
• Kidney function was assessed by measuring urine osmolality, blood urea nitrogen (BUN), and serum creatinine.
• Para-aminohippurate (PAH) uptake by renal cortical slices and its inhibition by probenecid were evaluated.

Main Results:

• After 4-5 days, gentamicin caused decreased urine osmolality and increased BUN and serum creatinine.
• Gentamicin treatment significantly enhanced tubular secretion and cortical slice uptake of PAH, an organic acid.
• Probenecid, an inhibitor of organic acid transport, blocked the increased PAH uptake.

Conclusions:

• Gentamicin administration in rats leads to functional kidney impairment.
• The data strongly suggest that gentamicin specifically stimulates the organic acid transport system.
• This stimulation of organic acid transport may be an early indicator of gentamicin-induced nephrotoxicity.