Endocrine Infertility Flashcards
(43 cards)
Reproductive Axis for Males?
GnRH stimulates LH and FSH release
Acts on Sertoli & Leydig cells in testis = produces testosterone & inhibin (-ve feedback)
Reproductive Axis for Females?
28-day menstrual cycle
Consists of follicular phase (similar axis to male), ovulation (unique) & luteal phase (either menstruation or pregnancy)
What is unique about the reproductive axis for females?
Occurs during OVULATION
High levels of oestradiol triggers a POSITIVE FEEDBACK = larger GnRH & LH release
Define Infertility
Inability to conceive after ONE YEAR of regular unprotected sex
Stats associated w. infertility?
1:6 couples
Males (30%)
Females (45%)
Unknown (25%)
2 reasons that could give rise to infertility?
- Primary gonadal failure
2. Hypo/pituitary disease
Primary gonadal failure?
GONADS fail
HIGH GnRH and LH/FSH
LOW/NO inhibin & testosterone/oestradiol (so less -ve feedback)
Hypo/pituitary disease?
Hypothalamus/pituitary fails
LOW/NO GnRH and LH/FSH
LOW/NO inhibin & testosterone/oestradiol
Typical disorder leading to male infertility?
Hypogonadism
Clinical features of hypogonadism in men?
x loss of libido x impotence x small testes x decrease muscle bulk x osteoporosis
Essentially NO testosterone so leads to this
4 causes of hypogonadism in men?
- Hypothalamic-pituitary disease
- Primary gonadal disease
- Hyperprolactinaemia (less so in men)
- Androgen receptor deficiency
What can consist in hypothalamic-pituitary disease?
x Hypopituitarism
x Kallmans syndrome (ansomia [lack of smell] & LOW GnRH)
x Illness/underweight (low leptin, so body says not time to reproduce)
What can consist in primary gonadal disease?
Cogenital - Klinegelters syndrome (XXY)
Acquired - testicular torsion, chemotherapy
Potential investigations for hypogonadism in males?
- Check LH, FSH & testosterone levels - is ALL LOW, do MRI of pituitary as might be pituitary problem
- Prolactin (excess)
- Sperm count:
x Azoospermia = ABSENCE of sperm when ejaculate
x Oligospermia = REDUCED no. of sperm when ejaculate - Chromosomal analysis e.g. Klienfelter’s syndrome
Potential treatments for hypogonadism in males?
- HRT - replace testosterone for ALL patients
- For fertility - if hypo/pituitary disease give SUBCUTANEOUS gonadotrophins (LH/FSH)
- Hyperprolactinaemia - dopamine agonist to inhibit prolactin
How do the potential treatments differ for male hypogonadism if want to get pregnant?
Testosterone is NOT enough - need to replace LH/FSH as well so do so subcuntaneously
What are the endogenous sites of androgen production?
x Leydig cells of testes x Adrenal cortex x Ovaries x Placenta x Tumours
4 main actions of testosterone?
- Developement of male genital tract
- Maintains fertility in adulthood
- Control of 2o sexual characteristics
- Anabolic effects (muscle, bone)
Characteristics of testosterone when circulating?
98% protein bound!
What 2 pathways can testosterone enter when circulating?
5alpha-reductase:
testosterone –> DHT
x acts on AR (androgen receptor)
Aromatase:
testosterone –> 17beta-oestradiol
x acts on ER (oestrogen receptor)
What are the clinical uses of testosterone?
In adulthood, increases: x lean body mass x muscle size & strength x bone formation & mass (in young men) x libido x potency
Whilst in men, endocrine disorders are typically hypogonadism, what are the potential disorders in female?
- Amenorrhoea
- PCOS (Polycystic Ovarian Syndrome)
- Hyperprolactinaemia
Define amenorrhoea?
Absence of periods
Difference between 1o and 2o amenorrhoea?
1o - failure to begin spontaneous menstruation by age 16
1o - absence of menstruation for 3 months in woman who previously had cycles