Sexual behaviors of wild-type and FucM knockout females. (A) Lordosis quotients of gonads-intact (left) and ovariectomized females (right). Lordotic responses by three consecutive tests were observed for the ovariectomized wild-type controls and FucM gene-disrupted mice after treatments with E2 (test 1 and 2) and E2 plus progesterone (test 3). The tests were carried out at a one-week interval. The scores of the KO females were different with P < 0.001 (*) from that of the wild-type and P > 0.05 (#) from that of heterozygote. (B) Frequencies of attempted mounts, mounts and intromission-like behaviors in three consecutive tests of subject females with a female partner. (C) Photomicrographs of sections in AVPv stained by immunohistochemistry for tyrosine hydroxylase in males, wild-type females, and FucM KO females. (D) Numbers of tyrosine hydroxylase-immunoreactive (ir) neurons in the sections shown in C: *, P < 0.001 compared to that of the wild-type males; #, P < 0.001 compared to that of wild-type females. Data are shown as mean ± s.e.m.