Identification of an autosomal locus affecting steroid sulfatase activity among inbred strains of mice.

We have found an activity variant for testicular and liver steroid sulfatase among inbred strains of mice that is not X-linked. C57BL/6J, SM/J and SWR/J testicular extracts hydrolyze 3H-dehydroepiandrosterone sulfate twice as rapidly as do A/J extracts. The C3H/HeJ and DBA/2J strains were intermediate. The Km values for C57BL/6J and A/J are 2.29 +/- 0.10 and 1.01 +/- 0.02 microM, respectively. The F1 values in both directions were intermediate, which argues against X-linkage of this trait. F2 values show scattered high-intermediate-low values compatible with assay variation superimposed on the segregation of codominant alleles. When assayed for both testicular and liver steroid sulfatase, nine recombinant inbred lines between A/J and C57BL/6J segregate to near the parental strain values. Thus, this activity variation for steroid sulfatase appears to be determined by a single gene, which is not X-linked. Sex and steroidal hormone differences in liver steroid sulfatase activity were not present in the A/J strain, but females of the C57BL/6J and some recombinant inbred lines had higher levels. Electrophoretic studies only disclosed a variant in the SM/J strain, which seems to be secondary to the well-known neuraminidase variation in SM/J.