25 一位 55 歲的男性因性慾降低及勃起功能障礙而求診，經抽血檢驗發現其血中睪酮（testosterone）量 只有 150 ng/dL（正常值為 300 ng/dL）。醫師給予之診斷為男性更年期（或稱男性性腺分泌不足）， 故給予定時之睪酮注射補充治療（replacement therapy）。經由一段時間的睪酮補充之後，下列何種 現象是較不會發生的？
(A)落髮量增多，結果頭頂禿髮的情形變嚴重
(B)陰部及臉上鬍鬚之毛髮量增多
(C)血中血紅素（hemoglobin）數值增加
(D)睪丸內精子之製造量增加

Spermatogenesis 精子生成所需的荷爾蒙

1.  Testosterone, secreted by the Leydig cells located in the interstitium of the testis, is essential for growth and division of the testicular germinal cells, which is the first stage in forming sperm.

2.  Luteinizing hormone, secreted by the anterior pituitary gland, stimulates the Leydig cells to secrete testosterone.

3.  Follicle-stimulating hormone, also secreted by the anterior pituitary gland, stimulates the Sertoli cells; without this stimulation, the conversion of the spermatids to sperm (the process of spermiogenesis) will not occur.

外源性的testosterone負迴饋抑制FSH分泌導致精子無法生成

4.  Estrogens, formed from testosterone by the Sertoli cells when they are stimulated by follicle-stimulating hormone, are probably also essential for spermiogenesis.

5.  Growth hormone (as well as most of the other body hormones) is necessary for controlling background metabolic functions of the testes. Growth hormone specifically promotes early division of the spermatogonia themselves; in its absence, as in pituitary dwarfs, spermatogenesis is severely deficient or absent, thus causing infertility.