EFFECT OF DEHYDROEPIANDROSTERONE-SULFATE ON CARNITINE ACETYL TRANSFERASE-ACTIVITY AND L-CARNITINE LEVELS IN OOPHORECTOMIZED RATS

Alteration in energy metabolism of postmenopausal women might be relat ed to the reduction of dehydroepiandrosterone sulfate (DHEAS). DHEA an d DHEAS decline with age, leveling at their nadir near menopause. DHEA and DHEAS modulate fatty acid metabolism by regulating carnitine acyl transferases and CoA. The purpose of this study was to determine wheth er dietary supplementation with DHEAS would also increase tissue L-car nitine levels, carnitine acetyltransferase (CAT) activity and mitochon drial respiration in oophorectomized rats. Plasma L-carnitine levels r ose following oophorectomy in all groups (P < 0.0001). Supplementation with DHEAS was not associated with further elevation of plasma L-carn itine levels, but with increased hepatic total and free L-carnitine (P = 0.0021 and P < 0.0001, respectively) and cardiac total L-carnitine concentrations (P = 0.045). In addition, DHEAS supplementation increas ed both hepatic and cardiac CAT activities (P < 0.0001 and P = 0.05 re spectively). CAT activity positively correlated with the total and fre e carnitine levels in both liver and heart (r = 0.764, r = 0.785 and r = 0.700, r = 0.519, respectively). Liver mitochondrial respiratory co ntrol ratio, ADP:O ratio and oxygen uptake were similar in both contro l and supplemented groups. These results demonstrate that in oophorect omized rats, dietary DHEAS supplementation increases the liver and hea rt L-carnitine levels and CAT activities. In conclusion, DHEAS may mod ulate L-carnitine level and CAT activity in estrogen deficient rats. T he potential role of DHEAS in the regulation of fatty acid oxidation i n postmenopausal women is worthy of investigation.