Ovulation disorders and male hypogonadism Flashcards Preview

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Flashcards in Ovulation disorders and male hypogonadism Deck (91)
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1

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

2

What type of hormones are oestrogens?

Steroid

3

Where and by which cells does glandular oesteogen synthesis occur?

Ovaries - theca and granulosa cells
Corpus luteum

4

Which type of cells does LH stimulate? Which hormone production does it induce?

Granulosa
Pregnenolone

5

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

6

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

7

Where and how does extra-glandular oestrogen synthesis occur?

Aromatase expression in fat and bone allows conversion of androstenedione to oestrone

8

Explain progesterone synthesis

3beta-HSD converts pregnenolone to progesterone in the corpus luteum, placenta (during pregnancy) and adrenals (pathway to androgen and mineralocorticoid synthesis)

9

What receptors numbers increase in the presence of oestrogen?

Intracellular progesterone receptor

10

How do the products of hormone synthesis vary with the menstrual cycle?

Follicular phase - oestradiol
Luteal phase - progesterone

11

When are LH and FSH highest?

Just before and during ovulation

12

What does oligomenorrhea mean?

Less than 9 periods a year

13

What does primary amenorrhea mean?

Failure of menarche before age 16

14

What does secondary amenorrhea mean?

Cessation of periods for over 6 months in an individual who has previously menstruated

15

What categories do the causes of amenorrhea fall under?

Physiological
Primary (genetic)
Secondary (ovarian, uterine, hypothalamic, pituitary)

16

How should amenorrhea be investigated?

LH/FSH
Oestradiol
Thyroid function
Prolactin

Ovarian ultrasound
Testosterone
Pituitary function
MRI
Karyotype

17

What is female hypogonadism?

Low levels of oestrogen

18

Where does the problem lie with primary and secondary hypogonadism respectively?

Primary - ovaries
Secondary - hypothalamic or pituitary

19

What is hypergonadotrophic hypogonadism?

Low oestradiol
High FSH/LH

20

What is hypogonadotrophic hypogonadism

Low oestradiol
Low FSH/LH

21

What is premature ovarian failure?

Amenorrhea, oestrogen deficiency and elevated gonadotrophs occurring before the age of forty

22

What is the diagnostic criteria for premature ovarian failure?

FSH > 30 on two separate occasions at least 1 month apart

23

What are the causes of premature ovarian failure?

Chromosomal
Genetic mutation (FSH/LH receptor)
Iatrogenic
Autoimmune

24

What are the chromosomal causes of premature ovarian failure?

Turner's
Fragile X

25

What are the iatrogenic causes of premature ovarian failure?

Surgery
Radiation

26

What are the autoimmune causes of premature ovarian failure?

Addison's
Thyroid disease

27

What is kallman's syndrome a problem with?

Hypothalamus

28

Wilson's syndrome can cause hypogonadism. T/F

False - haemochromatosis

29

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

30

Where is the problem with idiopathic hypogonadotrophic hypogonadism?

Hypothalamus - inability to activate GnRH secretion

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