The expression of GON-SJTU1 protein in rat testes at different ages. (A) Representative western analyses of protein from samples obtained from testes on postnatal days 5, 10, 15, 20, or 60. The expression of β-tubulin was used as an internal standard for normalization. (B) In each of three replicate analyses, Western blots were quantified, and the results were expressed as the ratio of GON-SJTU1: β-tubulin. The bars represent the means ± SEM of the data for each age, and bars marked with star were significantly different from each other (p < 0.05).