Sex and Age Differences in the Distribution of 14C-Sterigmatocystin in Immature and Mature Rats

Abstract

Sterigmatocystin, a mycotoxin produced by several fungi, is carcinogenic when injected subcutaneously in rats. The potential of sterigmatocystin as a contaminant to human foodstuffs makes understanding its absorption, distribution, metabolism, and excretion characteristics desirable. Single doses (8 mg/kg) of ¹⁴C-sterigmatocystin were dissolved in wheat germ oil and administered orally to immature (50–150 g) and mature (200–300 g) rats of both sexes. Five rats of each sex and age group were sacrificed at 3, 6, 12, 48, and 96 hours after dosing. Biological specimens were collected and analyzed for total radioactivity. The differences in tissue levels of ¹⁴C-sterigmatocystin due to age and sex were examined using Tukey's paired comparison procedure for the mean area under the tissue level vs. time curves. Statistically significant differences in the gastrointestinal tract tissue levels were observed in 70% or more of these tissues when comparing mature males vs. mature females and immature females vs. mature females. Age and sex differences were also observed in 30% or less of the organ tissues in the other comparisons made. The sterigmatocystin plasma levels vs. time curves for each group have at least two distinct peaks that may be indicative of enterohepatic recirculation. The plasma levels obtained in the male rats are consistently higher than those in the females.