ELEVATED CONCENTRATIONS OF ASCORBATE AND NORMOXIA SUPPRESS TESTOSTERONE PRODUCTION IN CULTURED GUINEA-PIG LEYDIG-CELLS

In recent years, several metabolic roles have been proposed for vitami n C. Recent information suggests a strong causal relationship between high endogenous levels of ascorbic acid and changes in normal reproduc tive biology. Using highly enriched populations of guinea pig Leydig c ells, we have found that elevated levels (50 to 500 muM) of ascorbate significantly (P < 0.01) depressed testosterone production in a dose-d ependent manner while low levels (0 to 10 muM) were without effect. Le ydig celts incubated under hypoxic (3% oxygen) culture conditions prod uced significantly (P < 0.01) more testosterone than similar cells cul tured under normoxic (19% oxygen) conditions. The results of this stud y suggest that high concentrations of ascorbate and normoxic culture c onditions suppress testosterone production in isolated Leydig cells. T hus, it would seem that there exists a delicate balance between normal metabolic requirements for vitamin C and excessive ascorbate levels t hat might alter normal gonadal reproductive events.