Abstracts

RATIONALE: Earlier studies showed a gender difference in seizure thresholds evoked by pentylenetetrazole (PTZ) infusion in rats fed a ketogenic diet. The goal of this study was to determine whether the relationship between diet, ketonemia and seizure threshold differed between male and female rats.
METHODS: Forty Sprague-Dawley rats (20 male and 20 female) were divided into two diet groups of 10 animals each, of each gender, at age P37. Following an initial eight-hour fast by all animals, 10 rats of each sex were returned to Purina Rodent chow (5001) and fed ad libitum (NAL) and 10 of each sex were fed a ketogenic diet (BioServe F3666) at 90% of caloric daily requirement (K90), each for 20 days. Ketonemia was measured spectrophotometrically in whole blood as [beta]- hydroxybutyrate (GDS Technologies) and seizures were induced by tail-vein infusion of PTZ until first overt clonus. Comparisons were by Student[ssquote]s t-test (unpaired).
RESULTS: Both ketonemia and seizure threshold were elevated in male rats fed the ketogenic diet, compared to those fed the normal diet, as has been shown previously. Ketonemia was similarly elevated in female rats. The seizure threshold for ketonemic females was the same as that of ketonemic males, but was not elevated compared to that of females fed the normal diet.
CONCLUSIONS: Seizure threshold and ketonemia are unrelated in female rats, unlike males, in which there is a positive correlation. This is further evidence that factors other than ketonemia are important modulators of seizure threshold in rats fed ketogenic diets.
Support: Department of Biology, Georgetown University