Callosum agenesis,testosterone and thyroxin

OBJECTIVES: Approximately 20% of BALB/cCF mice are born with partial or total absence of the corpus callosum. Here, we analyzed testosterone and free thyroxin blood levels in adult male mice of this strain in order to see if these hormones are related to the incidence of callosal defects. METHODS: Blood collected from the axillary blood vessels of 12 normal and 10 acallosal deeply anesthetized adult male mice was used in order to determine testosterone and free thyroxin levels through chemiluminescence (IMMULITE, Diagnostics Products Corporation, USA). RESULTS: No significant difference (one-way ANOVA: F = 0.11, df = 1, p > 0.10) was found between normal ( = 1.95, SD = 0.62) and acallosal ( = 1.86, SD = 0.62) mice for free thyroxin level. On the other hand, in those mice that had detectable testosterone levels (above 0.2 ng/ml), a significant difference was found (t = 2.8, df = 6.06, p = 0.03): normal mice (n = 7, = 8.73, SD = 7.64) had a higher level than acallosal mice (n = 4, = 0.62, SD = 0.41). CONCLUSIONS: The present results indicate that the incidence of callosal agenesis is not related to free thyroxin levels in the blood of adult BALB/cCF mice. On the other hand, in spite of the fact that low testosterone levels seems to be frequent in male mice of this strain, acallosal mice tend to have lower levels of this hormone than normal mice.