GnRH - FSH and LH would not be secreted by the anterior pituitary.
Follicle-stimulating hormone (FSH) is a gonadotropin hormone secreted by the anterior pituitary which regulates development and pubertal maturation. Luteinizing hormone (LH) is also a hormone produced by cells of the anterior pituitary. In females, LH regulates ovulation, while in males it stimulates the production of testosterone. LH and FSH act together and regulate important processes of the reproductive system.
Gonadotropin-releasing hormone (GnRH) is secreted by the hypothalamus and is responsible for the release of the FSH and LH. Therefore, if GnRH was absent in a pubescent male, FSH and LH would not be released.
LH/FSH - Testosterone secretion would not occur.
As described above, LH and FSH work synergistically to control many factors of the reproductive system. LH is responsible for stimulating the production of testosterone by the Leydig cells, which are located in the testicles.
More specifically, when testosterone levels are low, GnRH is released by the hypothalamus which in turn triggers the secretion of LH and FSH by the anterior pituitary. The secretion of these two hormones triggers the production of testosterone by the testicles.
Therefore, if LH was absent, the secretion of testosterone would not occur.
FSH - Spermatogenesis would not occur due to the absence of androgen-binding protein.
Spermatogenesis is the process of the development of mature male gametes (haploid spermatozoa) in the testis. FSH triggers the secretion of androgen-binding protein (ABP) by the Sertoli cells, which are specialized cells in the testicles. ABP is responsible for increasing the concentration of testosterone in levels high enough so that the spermatogenesis will occur.
Therefore, if FSH is absent, ABP will not be secreted and spermatogenesis will not occur.
Testosterone - A person would experience a loss of sex drive.
Testosterone is the primary male sex hormone which is involved in many processes of the reproductive system. Testosterone's most important role is the development of male reproductive tissues and secondary sexual characteristics. This steroid hormone is also responsible for health and well-being and the sense of sexual drive. If testosterone was absent in a pubescent male, then the person would have serious developmental issues and would also experience a loss of sex drive.
Inhibin - Spermatogenesis would occur in excess.
The Sertoli cells, which are located in the testis, secrete the polypeptide hormone inhibin, which acts on the pituitary control of the spermatogenesis. When the sperm count is too high, the inhibin is released into the blood and inhibits the production of GnRH and FSH. This inhibition will cause the spermatogenesis process to stop.
Therefore, if the inhibin is absent, the control of spermatogenesis will not happen and would occur in excess.
