Endocrine infertility

Question 1

What are the phases of the menstrual cycle?

Answer 1

Follicular phase
Ovulation
Luteal phase

Question 2

What are the possible outcomes of the luteal phase of the menstrual cycle?

Answer 2

If implantation does not occur, menstruation follows (shedding of endometrium).
If implantation occurs, pregnancy follows.

Question 3

What is infertility?

Answer 3

Inability to conceive after 1 year of regular unprotected sex.

Question 4

What are the clinical features of male hypogonadism?

Answer 4

Loss of libido
Impotence
Small testes
Decreased muscle bulk
Osteoporosis

Question 5

What can male hypogonadism be caused by?

Answer 5

Hypothalamic/pituitary disease, e.g. hypopituitarism
Kallman’s syndrome (anosmia, low GnRH, low-normal stature, undescended testes)
Illness/underweight
Primary gonadal disease, e.g. Klinefelter’s syndrome (congenital, XXY), testicular torsion (acquired), chemotherapy (acquired)
Hyperprolactinaemia
Androgen receptor deficiency

Question 6

What stimulates the release of LH and FSH from the pituitary in males?

Answer 6

GnRH pulses from the hypothalamus.

Question 7

What does LH stimulate in males?

Answer 7

Testosterone production in Leydig cells of the testes.

Question 8

What is the role of testosterone in males?

Answer 8

Secondary sexual characteristics
Aids spermatogenesis
Negative feedback on the hypothalamus and pituitary

Question 9

What is the role of FSH in males?

Answer 9

Stimulates Sertoli cells in seminiferous tubules to produce sperm and inhibin A and B.

Question 10

What is the role of inhibin in males?

Answer 10

Negative feedback on pituitary FSH secretion.

Question 11

What does LH stimulate in females in the follicular phase of the menstrual cycle?

Answer 11

Production of oestradiol and progesterone in the ovaries.

Question 12

What does FSH stimulate in females in the follicular phase of the menstrual cycle?

Answer 12

Follicular development.

Inhibin.

Question 13

By around day 10 of the menstrual cycle, what has the leading follicle developed into?

Answer 13

Graffian follicle

Question 14

What is the role of oestrogen in females in the follicular phase of the menstrual cycle?

Answer 14

Negatively inhibits LH and FSH secretion.

Question 15

What happens in the luteal phase of the menstrual cycle?

Answer 15

Once the oestrogen levels reach a certain point, it switches from negative feedback to positive feedback.
It increases GnRH release and increases LH sensitivity to GnRH.
This leads to a mid-cycle LH surge.
This triggers ovulation from the leading follicle.

Question 16

What is primary gonadal failure?

Answer 16

A defect of the gonads.
The testes or ovaries are not producing testosterone/oestrogen so there is no negative feedback on the HPG axis.
High GnRH.
High LH and FSH.

Question 17

What is azoospermia?

Answer 17

Absence of sperm in ejaculate.

Question 18

What is oligospermia?

Answer 18

Reduced numbers of sperm in ejaculate.

Question 19

What investigations may be carried out to check for male hypogonadism?

Answer 19

LH, FSH and testosterone measured. If all low, MRI the pituitary.
Prolactin.
Sperm count.
Chromosomal analysis.
Look at sperm under microscope to check numbers and motility.

Question 20

How is male hypogonadism treated?

Answer 20

Replacement testosterone for all patients- increases muscle bulk and protects against osteoporosis.
For fertility, if hypothalamic/pituitary disease: gonadotrophins to stimulate testosterone release- give subcutaneous gonadotrophin injections to induce spermatogenesis.
Hyperprolactinaemia: dopamine agonist.

Question 21

What are the endogenous sites of androgen production?

Answer 21

Interstitial Leydig cells of the testes
Adrenal cortex (males and females)
Ovaries
Placenta
Tumours

Question 22

What are the main actions of testosterone?

Answer 22

Development of the male genital tract
Maintains fertility in adulthood
Control of secondary sexual characteristics
Anabolic effects (muscle, bone)