Fig. 1.

MC-mediated anaphylaxis is sexually dimorphic without the presence of adult gonadal hormones. Male and female mice were GDX or SHAM at 12 wk of age. Mice (13 wk to 14 wk old) were sensitized with DNP-specific IgE (10 μg i.p.) and challenged the following day with DNP-HSA (500 μg i.p.; n = 5 to 7 per group). (A) Male and female GDX mice had sexually dimorphic hypothermia responses that were not different from male and female SHAM mice. Repeated measures two-way ANOVA with Tukey’s multiple comparisons test. (B) Peak temperature change was greater in female mice regardless of group. Two-way ANOVA with Sidak’s multiple comparisons test. (C) Serum histamine levels 30 min after anaphylaxis were greater in female mice, regardless of GDX status, compared with male cohorts. No difference in serum histamine levels was found between GDX and SHAM groups within their sex. Two-way ANOVA with Sidak’s multiple comparisons test. (D) Gonadectomizing did not affect the number of MCs in mesenteric tissue MCs in male or female mice, and MC number was not different between the sexes. Two-way ANOVA with Sidak’s multiple comparisons test. (E) Gonadectomizing had no overall effect on tissue MC degranulation measured as the percentage of degranulated MCs 30 min after induction of anaphylaxis. Two-way ANOVA with Sidak’s multiple comparisons test. MCs were counted in 10 randomly chosen fields (200× magnification) per mouse. Unpaired Student’s t test. Data represent mean ± SEM; ns: nonsignificant; ****P < 0.0001.