Flashcards in Ovulation disorders and male hypogonadism Deck (91)
Briefly describe the hypothalamic-pituitary-gonadal axis
Hypothalamus secretes gonadotrophin releasing hormone >
GnRH acts upon the anterior pituitary >
Anterior pituitary secretes LH and FSH >
LH and FSH stimulate gamete formation (FSH only in males) directly and via the production of steroid and peptide hormones within the gonads
What type of hormones are oestrogens?
Where and by which cells does glandular oesteogen synthesis occur?
Ovaries - theca and granulosa cells
Which type of cells does LH stimulate? Which hormone production does it induce?
Describe the process of oestradiol production
Pregnenolone diffuses form the granulosa cells to theca cells >
Theca cells convert pregnenolone to androstenedione using 17,20-lyase and 3beta-HSD >
Androstenedione returns to the granulosa cells where it is converted to oestrone by aromatase >
Oestrone is further converted to oestradiol by 17beta-HSD
What does FSH do? How does it do this?
Stimulates the conversion of androstenedione to oestrone via aromatase
Stimulates the conversion of oestrone to oestradiol via 17beta-HSD
Where and how does extra-glandular oestrogen synthesis occur?
Aromatase expression in fat and bone allows conversion of androstenedione to oestrone
Explain progesterone synthesis
3beta-HSD converts pregnenolone to progesterone in the corpus luteum, placenta (during pregnancy) and adrenals (pathway to androgen and mineralocorticoid synthesis)
What receptors numbers increase in the presence of oestrogen?
Intracellular progesterone receptor
How do the products of hormone synthesis vary with the menstrual cycle?
Follicular phase - oestradiol
Luteal phase - progesterone
When are LH and FSH highest?
Just before and during ovulation
What does oligomenorrhea mean?
Less than 9 periods a year
What does primary amenorrhea mean?
Failure of menarche before age 16
What does secondary amenorrhea mean?
Cessation of periods for over 6 months in an individual who has previously menstruated
What categories do the causes of amenorrhea fall under?
Secondary (ovarian, uterine, hypothalamic, pituitary)
How should amenorrhea be investigated?
What is female hypogonadism?
Low levels of oestrogen
Where does the problem lie with primary and secondary hypogonadism respectively?
Primary - ovaries
Secondary - hypothalamic or pituitary
What is hypergonadotrophic hypogonadism?
What is hypogonadotrophic hypogonadism
What is premature ovarian failure?
Amenorrhea, oestrogen deficiency and elevated gonadotrophs occurring before the age of forty
What is the diagnostic criteria for premature ovarian failure?
FSH > 30 on two separate occasions at least 1 month apart
What are the causes of premature ovarian failure?
Genetic mutation (FSH/LH receptor)
What are the chromosomal causes of premature ovarian failure?
What are the iatrogenic causes of premature ovarian failure?
What are the autoimmune causes of premature ovarian failure?
What is kallman's syndrome a problem with?
Wilson's syndrome can cause hypogonadism. T/F
False - haemochromatosis
What is idiopathic hypogonadotrophic hypogonadism?
Absent/delayed sexual maturation with low gonadotrophs in the absence of anatomical or functional problem with the hypothalamic-pituitary-gonadal axis