Question

Question 11
Androgens are biochemically free to diffuse out of the testes, due to their hydrophobic nature, however they largely remain in the lumen of the seminiferous tubule. Which best explains why this is so?

Sefton cells secrete a protein with a high affinity for dihydrotestosterone.
Testosterone is rapidly converted to dihydrotestosterone which cannot enter the bloodstream
Testosterone is rapidly converted by aromatase which cannot diffuse across membranes
Leydig cells secrete a protein with a high affinity for testosterone.

Answer 1

Answer:

Option A (Sefton cells secrete a protein with a high affinity for dihydrotestosterone)

Explanation: Dihydrotestosterone is a hormone which stimulates the formation and production of the steroid hormone; testosterone from the Leydig cells within the seminiferous tubules of the testes.

The hormone is a steroid hormone and is capable of easily diffusing from the lumen of the seminiferous tubules of the testes however it does not happens this way. This is because the Sertoli cells within the seminiferous tubules of the testes also called as the sefton/nurse cells are known to release a hormone; ABP (Androgen binding protein).

This protein has a very high efficiency for binding and concentrating the androgens produced by the Leydig cells. And hence for that reason, despite having the ability, the hormone dihydrotestosterone never leaves the lumen of the seminiferous tubules of testes.