Chapter 9. Reproductive Physiology
A 34-year old-woman begins assisted fertility treatment to initiate ovulation. She is treated with an agent that acts via gonadotropin-releasing hormone (GnRH) receptors in the anterior pituitary. Which of the following treatments is most likely to be effective?
A GnRH agonist given in pulsatile doses
B GnRH agonist given continuously
C GnRH receptor blocker given in pulsatile doses
D GnRH receptor blocker given continuously
A. Pulsatile GnRH mimics the physiologic release pattern. Continuous dosing is ineffective because it downregulates pituitary gonadotropes.
A 58-year-old man complained of loss of libido and reduced muscle strength. Serum analysis showed reduced levels of testosterone. Reduced activity in which of the following hormone-target cell axes could account for his symptoms?
A Luteinizing hormone (LH) – Leydig cell
B Follicle-stimulating hormone (FSH) – Leydig cell
A. Leydig cells produce testosterone in response to LH.
A 17-year-old girl visited her physician because she had never had a menstrual period. Physical examination revealed a tall female with a short, blind-ended vagina and no palpable cervix. Ultrasound showed the absence of a uterus and no ovaries but the presence of undescended testes. Deficiency of which enzyme, hormone, or receptor is most likely to account for these findings?
E Müllerian-inhibiting substance
A. The patient has complete androgen insensitivity (testicular feminization) in which androgen-induced development of the mesonephric duct fails. Sertoli cells continue to secrete müllerian-inhibiting substance, so female internal reproductive organs also fail to develop.
A 57-year-old man was prescribed the phosphodiesterase type 5 inhibitor sildenafil to enhance sexual function. Which of the following effects will most likely occur after he has taken sildenafil?
A Penile erection in the absence of erotic stimulation
B Enhanced penile erection following normal erotic ...