GH protein in the hypothalamus. (A) A representative blot is shown. (B) Densitometry data from the blots is presented. Adult mice from the four core genotypes—XY males (XYM N = 4, black bars), XX males (XXM N = 3, horizontal striped bars), XX females (XXF N = 3, white bars), and XY females (XYF N = 3, diagonal striped bars)—were gonadectomized and treated with estradiol (E). The single asterisk denotes significant effect of sex chromosome complement (P < 0.05). The double asterisks denote significant effect of gonadal sex (P < 0.05). The plus symbol denotes XY females which are significantly different from all other groups (P < 0.05).