Figure 2.

NRG1 is expressed in HSD17B3-positive Leydig cells (ALCs) in mouse testes. A, Western blot analysis of NRG1 protein levels in testes collected from 1 to 12 weeks of age. The membrane was incubated with a commercial anti-NRG1 polyclonal antibody (Abcam) that recognizes the IgG repeat and EGF domain of NRG1. β(B)-Actin was used as a loading control. Results are representative of three separate experiments. B, Cross-sections of mouse testes were stained with antibodies to visualize either NRG1 (green) or HSD17B3 (red), a marker of adult Leydig cells, at postnatal week 1 (infant) and 12 weeks (adult). White lines delineate the border of the seminiferous tubules. Scale bars correspond to 100 μm. Arrows (yellow) indicate NRG1-positive cells and/or HSD17B3-positive cells in the seminiferous tubules and interstitial tissue. N.C., negative controls without primary antibody. C, The percentage of NRG1-HSD17B3 double-positive cells per NRG1 positive cells in the interstitial tissue of testes at each age. The number of positive cells in a section per testis was counted and a total of three different samples were analyzed. Values are mean ± SEM of three different samples. D, The percentage of NRG1-HSD17B3 double-positive cells per all of interstitial cells. The number of positive cells or total number of interstitial cells in each section per testis was counted and a total three different samples were analyzed. Values are mean ± SEM of three different samples. Different superscripts denote significant differences in each cells (P < .05).