Fig. 5.

Disrupted excretion of testosterone from seminiferous tubules and restoration by addition of gangliosides. (A) Transport of intratesticularly injected [¹⁴C]testosterone into semen. The radioactivity in semen after injection was measured at the time points indicated. These experiments were repeated at least three times and showed essentially the same results. A representative result is given. Black bars, WT; white bars, KO. (B) Improvement of [¹⁴C]testosterone excretion in the presence of gangliosides in the KO mice. [¹⁴C]testosterone was injected as in A, with or without gangliosides (10 μg), then cpm in semen was examined at 5 and 30 min after injection. n = 3 for each group. Means ± SD are presented. Results were analyzed with a Student's two‐tailed t‐test. **, P < 0.05. (C) A scheme to show the essential role of complex gangliosides in testosterone transport from Leydig cells in testis. T, testosterone. An X superimposed on an arrow represents disrupted transport. This figure is reproduced from our previous paper [26].