Calcium-dependent effect of gentamicin on glucose formation in isolated rabbit kidney-cortex tubules.
In contrast to the inhibition by gentamicin of glucose production from propionate, pyruvate and lactate in renal tubules incubated at 2.5 mM Ca2+, this antibiotic does not affect gluconeogenesis from propionate and lactate, and significantly stimulates this process from other substrates at 0.5 mM Ca2+. This may be due to the gentamicin-induced increase of the cytosolic manganese content (from 1.7 to 2.7 nmol/mg protein), resulting in a stimulation of cytosolic phosphoenolpyruvate carboxykinase activity. At 2.5 mM Ca2+ the cytosolic Mn content (2.7 nmol/mg protein) seems to be high enough to accomplish activation of the enzyme.
Institute of Biochemistry, Warsaw University, Poland.
M
M
Michalik
I
I
Biedermann
J
J
Bryła
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D005839:Gentamicins / Q000494:pharmacology*; D005943:Gluconeogenesis / Q000187:drug effects*; D007672:Kidney Cortex / Q000378:metabolism*; D007687:Kidney Tubules, Proximal / Q000378:metabolism*; D008297:Male; D008345:Manganese / Q000378:metabolism; D010730:Phosphoenolpyruvate Carboxylase / Q000378:metabolism; D011817:Rabbits
D005839:Gentamicins; D008345:Manganese; D010730:Phosphoenolpyruvate Carboxylase; D002118:Calcium