A 22-year-old man came to his physician as a part of investigation of the cause of infertility of his marriage of two years. Physical examination revealed a healthy young man with normal secondary sex characteristics but without testes in the scrotal sac. Examination of a specimen of semen fails to demonstrate the presences of spermatozoa. The laboratory values are as follows: urinary gonadotrophins 12 RU/24 hours (normal) Plasma testosterone 7 pg /L at surgery the testes were found in the inguinal canals. Histologic examination of biopsy material showered fibrosis and degeneration of the epithelium of the seminiferous tubules
1. What hormones are necessary to sustain spermatogenesis? Are the amounts of hormone adequate in this man? How is this man’s situation similar to the lack of beard growth in the American Indian? Why has spermatogenesis failed in this patient?
2. What factors control FSH secretion in the male
3. What factors control LH secretion in the male
4. What hormones is directly responsible for male secondary sex characteristics
