endocrinology of the reproductive system Flashcards
hypothalamus-pituitary-ovarian axis
Hypothalamus -> GnRH -> LH and FSH released (ant pit gland) -> oestrogen + progesterone release (from ovaries) -> negative feed back to down regulate hormone production from hypothal + ant.pit
what are the 4 female reproductive hormones
- follicle stimulating hormone
- lutenizing hormone
- oestrogen
- progesterone
where is FSH produced and what does it act on in women?
- produced in the anterior pit gland
- acts on granulosa cells of ovary to stimulate follicle development
where is LH produced and what does it act on in women?
- produced in the anterior pit gland
- acts in Theca cells in overy to cause ovulation
where is oestrogen produced and what does it do?
- produced by follicle in response to FSH
- stimulates endometrial proliferation
- responsible for development of secondary sex characteristics
where is progesterone produced and what does it do?
- produced in granulosa cells in response to LH surge
- triggers endometrial transiion to secretory phase (i.e. thickening of endometrium in preparation for implantation of fertilized egg)
what happens in the follicular phase of the menstrual cycle (4)
- FSH stimulates growth of several follicles
- dominant follicle secrete oestrogen
- oestrogen inhibits growth of other follicles and FSH
- oestrogen stimulates development of endometrium
draw out the menstrual cycle graph
see lect notes
what happens in the ovulation phase of the menstrual cycle (2)
- surge in LH causes ovulation
- rupturing of the follicle creates a corpus luteum
what happens in the luteal phase of the menstrual cycle (8)
- corpus luteum secretes progesterone and oestrogen
- progesterone stimulates develpment of endometrium
- oestrogen and progesterone inhibit FSH/LH secretion
- corpus luteum degrades over tume, progesterone levels drop
- endometrium cannot be maintained without progestrone
- endometrium is sloughed away (mestruation)
- FSH is no longer inhibited and the menstrual cycle starts again
what hormone is released if fertilisation of the egg occurs and why
Human chorionic gonadotropin (hCG) -> maintains the corpus luteum
what is oliogmenorrhoea
<9 periods in a yearwh
what is amenorrhea
primary amenorrhoea - no periods by the age of 16
secondary amenorrhoea - no periods for >6 months in a women who has previously had a period
infertility definition
failure of pregnancy after 1 year of regular unprotected intercourse
what is hirsutism
presence of excessive terminal hair in androgen dependent areas of a womans body (mustache and beard, buttocks etc.)
what is virlilisation
male physical characteristics (muscle bulk, body hair, deep voice etc.) in a female
6 common presenting features of reproductive endocrine conditions in women
- oligo/amenorrhoea
- infertility
- hirstuism
- virilisation
- hot flushes/nigh sweats
- galactorrhoea (milk production from the breast unrelated to pregnancy or lactation)
3 physiological causes for amenorrhoea
- pre-pubertal
- pregnancy + lactation
- menopause
4 causes of primary amenorrhoea
- chromosomal (turner’s syndrome)
- hypothalamic pituitary failure (Kallman’s syndrome/pituritary disease)
- vaginal outflow tract and uterine disorders (congentical absence of vagina/uterus etc.)
- other (androgen insensitivity syndrome, congenital adrenal hyperplasia etc.)
5 causes of secondary ammenorrhoea
- ovarian -70% (PCOS, primary ovarian failure)
- hypothalamic (weight loss, excessive exrrcise, stress, craniopharyngioma, hypothalamic lesions etc.)
- pituritary (hyperprolactinaemia, hypopituitarism etc.)
- uterine (asherman’s syndrome, intrauterine adhersions etc.)
- other (thyroid dysfunction, cushing’s, CAH etc.)
hypothalamus-pituritary-testicular axis
hypothalamus -> GnRH -> LH and FSH released (from ant. pituitary gland -> testosterone release (from testes) -> -ve feed back to down regulate hypothal and pit. gland action
where is FSH produced and what is its action in males
- produced in the anterior pit gland
- target organ is the testes sertoli cells, it acts to stimulate development of sperm
where is LH produced and what is its action in males
- produced in the anterior pituritary gland
- acts on interstitial cells of the testes (leydig cells) to secrete testosterone
where is testosterone produced and what is its action in males
- produced in the testes
- promotes sperm development and development of secondary sex characteristics
what is testosterone converted to in peripheral tissues
dihydrotestosterone (DHT)
what is testosterone converted to in adipsoe tissue
oestradiol (converted by aromatase enzyme)
6 target organs of testosterone and its function there
- skin - growth of facial/body hair
- brain - sex drive, positive feelings, aids cognition and memory
- bone marrow - red blood cell producton
- male sex organs - sperm production, prostate growth, erectile function
- muscle - muscle mass and strength
- bone - bone density maintenance
4 common presenting features of reproductive endocrine conditions in men
- absence/regression of secondary sexual characteristics
- sexual dysfunction (erectile dysfunction, reduced libido etc.)
- reduced energy, muscle wasting, osteoporosis etc.
- infertility
hormone levels in primary hypogonadism
high FSH and LH, low Testosterone
hormone levels in secondary hypogonadism
low FSH and LH, low Tesosterone
3 causes of primary hypogonadism
- congential - chromosomal defect (e.g. klinefelter’s syndrome) or androgen receptor/enzyme defect
- acquired
- complications of illness (diabetes, CKD, haemochromatosis etc.)
6 acquired causes of primary hypogonadism
- testicular trauma - torsion
- surgical removal
- chemotherapy/irradiation
- infection (mumps orchitis)
- cryptochism ( one or both of the testes fail to descend from the abdomen into the scrotum)
- drugs - high dose glucocorticoids, sulphasalazine, alcohol
5 causes for secondary hypogonadism
- kallmann syndrome
- idiopathic hypogonadotrophic hypogonadism
- functional (exercise, weight loss, stress, anabolic steroids etc.)
- structural (tumours, infiltration (sacroid), head trauma etc.)
- misc - congenital adrenal hypoplasia, prader willi syndrome etc.
what is puberty
the period of transition between childhood and adulthood characterised by:
1. development of secondary sexual charcteristics
2. gonadoal maturation
3. attainment of reproductive capacity
what is tanner staging
sexual maturity rating -> objective classification system used for tracking the development and sequence of secondary sex characteristics of children during puberty
3 common congenital reproductive disease
- turner syndrome (45XO)
- Kallman syndrome
- klinefelter syndrome (47XXY)
what genetic mutation does turner syndrome have
monosomy - complete/partial absence of one X chromosome (aka 45XO)
who does turner syndrome affect
females -> can survive with just one X chromosome
physical appearance of someone w turner syndrome (6)
- short stature
- webbed neck
- micrognathia
- low set ears
- widely spaced nipples
- cubitus valgus
what endocrine dysfunction may be seen in turner syndrom
primary amenorrhoea or POF
what other codntions are associated with turner syndrome (6)
- congential heart defects
- hypothyroidism
- lymphoedema
- congential renal abnormalities
- hearing defects
what genetic mutation causes klinefelter syndrome
nondijunction mutation resulting in an extra X chromosome -> XXY chromosomes present
klinefelter syndrome presentation (9)
- tall stature (long legs)
- gynecomastia
- small, firm, testes
- signs of hypogonadism
- sparse beard growth
- loss of libido
- erectile dysfunction
- osteoporosis
- infertility
4 psychosocial problems with klinefelter syndrome
- limited verbal development
- attention defecit
- learnig difficulties
- social maladjustments
3 lab findings in klinefelter syndrome
- azoospermia (no sperm)
- oligoasthenoteratozoospermia (low sperm count, poor sperm motility and abnormal morphology of sperm)
- low testosterone, high LH and FSH
mgx for klinefelter syndrome
lifelong androgen replacement
what is kallman’s syndrome
a genetic form of hypogonadotrophic hypogonadism - a form of hypogonadism that is due to a problem with the pituitary gland or hypothalamus
what hormone fails to be secreted in kallman’s syndrome
GnRH
why is GnRH not produced in kallman’s syndrome
disordered migration of GnRH producing nuerons on hypothalamus
what non endocrine symptom is seen in kallman syndrome and why
anosmia (can’t smell) -> due to defective formation of olfactory bulb
kallman syndrome presentaion
- lack of smell
- absent or delayed puberty
- short fingers/toes
kallman syndrome mgx (4)
- hormonal replacement therapy is used to induce puberty
- for men - testosterone and hCG injections (may be in combination with FSH) in order to achieve normal virilisation and increased testicular volume
- for females - oestrogen is adminstered to induce breast development and genital development along w progesterone to establish the menstrual cycle
- pulsatile GnRH administration or exogenous gonadotropins are used to induce folliculogenesis and ovulation to restore fertility
what cells produce testosterone
leydig cells (in response to LH)
when is testosterone testing indicated (9)
- heigh loss, low trauma fracture, osteoporosis
- hot flushes/sweats
- gynaecomastia
- incomplete/delayed sexual development
- reduced libido
- decreased spontaneous erections
- loss of body hair
- shinking testesof <5mL vol
- low sperm count
when is treating testosterone deficiency contraindicated (5)
- haematocrit >52%
- actively seeking fertility
- uncontrolled heart failure
- untreated severe obstructive sleep apnoea
- sex hormone dependent cancer (caution not contraindicated)
2 key factors for diagnosing hypogonadism in men
- symptoms and signs consistent with testosterone deficeny
- unequivocally and consitsently low serum T concentrations (repeat morning fasting T concentrations)
