Sex and genetic differences in the elimination of sulphadimidine in rats

Rats of five inbred strains and two random-bred stocks were intravenously given sulphadimidine (40 mg/kg body weight). A relatively low percentage of acetylsulphadimidine (Ac-S) in urine and absence of strain differences were found in males, whereas two phenotypes can be distinguished in females: (1) high percentage of Ac-S in urine, and (2) low percentage of Ac-S in uirne. An autosomal control of these differences is suggested. A dominant allele which determines the high percentage of excreted Ac-S manifests itself only in female endo-environment.