#Id: 6582
                                                        #Unit 7. System Physiology – Animal
                                                        Sertoli cells secrete 
Androgenbinding protein (ABP), inhibin, and MIS
The fluid in the lumen of the seminiferous tubules is quite different from plasma; it contains very little protein and glucose but is rich in androgens, estrogens, K+ , inositol, glutamic and aspartic acids.  Maintenance of its composition depends on the blood–testis barrier.