Question

7. Prolonged use of a specific class of anti-psychotic agents can lead to excessive release of the hormone prolactin from the pituitary gland. (This can actually lead to excess lactation, even in men). Prolactin has a negative feedback effect on GnRH in the hypothalamus. Describe the how these antipsychotics would impact ovulation in females and sperm production in men. Ensure you include chemicals and cell types where appropriate. (150-200 words; 10 marks)

Answer 1

Antipsychotic drugs are mainly used for psychosis which is an excitable state. This excitable state is due to excessive release of dopamine in the brain. Therefore, to treat the psychosis, antipsychotics are used which are D2 receptor blockers. They block the action of dopamine by acting at D2 receptors in the brain.

Hypothalamus releases a hormone called Prolactin Inhibiting Factor (PIF) which inhibits the Prolactin Hormone release from the lactotrophs cells of the anterior pituitary. This PIF is Dopamine itself. Therefore , when the dopamine receptors are blocked, the Prolactin is not inhibited and excess prolactin will be released which causes Hyperprolactinemia in both males or females.

Prolactin has a negative feedback on the anterior pituitary hormones like FSH and LH. FSH and LH are released from the gonadotrophs cells of the anterior pituitary. This FSH is involved in stimulating the folliculogenesis in females and sperm production in males. FSH acts on the granulosa cells of the follicles and stimulate its proliferation in females. FSH acts on the Sertoli cells to stimulate the spermatogenesis. LH causes the LH surge which is responsible for the ovulation. LH in males, acts on Leydig cells to release Testosterone.

So, when there is Hyperprolactinemia, FSH and LH are suppressed and therefore ovulation in females and spermatogenesis in males is affected.