Fig. 4.

Testosterone regulates splenic catecholamine levels. a Noradrenaline and b dopamine concentration in spleens of castrated (ORX; n = 6) and sham-operated (n = 5) male mice. c Quantification of tyrosine hydroxylase (TH)-stained area in control (Pgk-Cre⁺) and general androgen receptor knockout (G-ARKO) male mice, expressed as percentage of follicle area. n = 7/group. d–f Sections of spleens from control and G-ARKO mice. Turquoise, nerve structures (tyrosine hydroxylase; TH); red, fibroblastic reticular cells (FRCs) and vascular structures (smooth muscle a-actin; SMA). B cells (IgD) are stained white in e and BAFF is stained white in f. Scale bar, 100 μm. g Higher-magnification image of SMA-positive FRC (red) and TH-stained nerve structures (turquoise); asterisk indicates area of co-localization. Scale bar, 20 μm. Bars indicate means; circles represent individual mice. *P < 0.05 (Mann–Whitney test)