Elevated Concentrations of Ascorbate and Normoxia Suppress
Testosterone Production in Cultured Guinea Pig Leydig Cells
by Dr. Mark A. Kukucka and Dr. Hara P. Misra
Department of Biomedical Sciences
Virginia-Maryland Regional College of Veterinary Medicine
Virginia Polytechnic Institute & State University
Blacksburg, Virginia 24061-0442
ABSTRACT: In recent years, several metabolic roles have been proposed
for vitamin C. Recent information suggests a strong causal
relationship between high endogenous levels of ascorbic acid and
changes in normal reproductive biology. Using highly enriched
populations of guinea pig Leydig cells, we have found that elevated
levels (50-500 uM) of ascorbate significantly (P < 0.01) depressed
testosterone production in a dose-dependent manner while low levels
(0-10 uM) were without effect. Leydig cells incubated under hypoxic
(3% oxygen) culture conditions produced significantly (P < 0.01) more
testosterone than similar cells cultured under normoxic (19% oxygen)
conditions. The results of this study suggest that high concentrations
of ascorbate and normoxic culture conditions suppress testosterone
production in isolated Leydig cells. Thus, it would seem that there
exists a delicate balance between normal metabolic requirements for
vitamin C and excessive ascorbate levels which might alter normal
gonadal reproductive events.
Running Title: High Ascorbate Levels Suppress Androgen Production
Key Words: Vitamin C, ascorbic acid, ascorbate,
antioxidants, Leydig cells, testosterone, androgen,
normoxia, hypoxia, reproduction, infertility, mark kukucka
Some other related professional publications by Dr. Mark Kukucka:
Kukucka, Mark A. and Hara P. Misra. 1996. Hypoxia and vitamin C
enhance the viability of isolated guinea pig Leydig cells in culture:
role of hydrogen peroxide. Free Rad Biol & Med
Kukucka, Mark A. and Hara P. Misra. 1994. Isolation and culture of
highly enriched populations of Leydig cells from guinea pigs (Cavia
porcellus) testes. Andrologia 26(4):217-224.
Kukucka, Mark A. and Hara P. Misra. 1994. Elevated concentrations of
ascorbate and normoxia suppress testosterone production in cultured
guinea pig Leydig cells. Reprod Toxicol 8(4):333-339.
Kukucka, Mark A. and Hara P. Misra. 1994. Determination of oxytocin
in biological samples by isocratic high-performance liquid
chromatography with coulometric detection using C18 solid-phase
extraction and polyclonal antibody-based immunoaffinity column
purification. J Chromatogr B Biomed Appl 653(2):139-145.
Kukucka, Mark A. and Hara P. Misra. 1993. The antioxidant defense
system of isolated guinea pig Leydig cells. Mol Cell Biochem 126(1):
1-7.
Kukucka, Mark A. and Hara P. Misra. 1993. Inhibition of hydrogen
peroxide production by vitamin C in Leydig cells cultured under
normobaric and hypoxic conditions. FASEB J 7(3):A348.
Kukucka, Mark A. and Hara P. Misra. 1992. HPLC determination of an
oxytocin-like peptide produced by isolated guinea pig Leydig cells:
stimulation by ascorbate. Arch Androl 29(2):185-190.
Kukucka, Mark A. and Hara P. Misra. 1992. HPLC identification of an
oxytocin-like peptide produced by isolated guinea pig Leydig cells:
stimulation by sodium ascorbate. In: E.S.E. Hafez (Ed), Molecular
Andrology, Volume IV, Issues 1-2, pp 160-161. M.C. Chang Festschrift,
Kiawah Is.
Elevated Concentrations of Ascorbate (Vitamin C) Suppress Testosterone Production in Cultured Guinea Pig Leydig Cells - Dr. Mark A. Kukucka 
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