The antioxidant defense system of isolated guinea pig Leydig cells.
Mol Cell Biochem. 1993 Sep 8;126(1):1-7.

Kukucka, Mark A. and Misra, Hara P.

Department of Biomedical Sciences, Virginia-Maryland Regional College
of Veterinary Medicine, Virginia Polytechnic Institute & State
University, Blacksburg 24061.

ABSTARCT

Utilization of highly enriched preparations of steroidogenic Leydig
cells have proven invaluable for studying the direct effects of
various hormones and agents on Leydig cell function in vitro. However,
recent work indicates that isolated Leydig cells are often subjected
to oxygen (O2) toxicity when cultured at ambient (19%) oxygen
concentrations. Because intracellular antioxidants play an important
role in protecting cells against oxygen toxicity, we have investigated
the intracellular antioxidant defense system of isolated Leydig cells.
The cellular levels of several antioxidants including catalase,
glucose-6-phosphate dehydrogenase (G-6-PDH), superoxide dismutase
(SOD) of the Cu/Zn & Mn variety, glutathione peroxidase, glutathione
reductase and total glutathione were quantitated using enriched
populations of Leydig cells isolated from adult male guinea pig
testes. Compared to whole testicular homogenates, Leydig cells
contained significantly (P < 0.01) less G-6-PDH, total SOD,
glutathione reductase and total glutathione, but significantly (P <
0.001) more glutathione peroxidase. Compared to hepatic values
previously reported in the guinea pig, Leydig cells contain nearly 400
times less catalase, about 14 times less glutathione peroxidase and
almost 11 times less glutathione reductase. Since G-6-PDH and
glutathione reductase are both necessary to regenerate reduced
glutathione (GSH) which couples with glutathione peroxidase to
breakdown hydrogen peroxide (H2O2) under normal conditions, it is
plausible that the oxygen toxicity observed in isolated Leydig cells
is due to the intracellular accumulation of H2O2.(ABSTRACT TRUNCATED
AT 250 WORDS)