Male infertility

Question 1

Causes of infertility in men.

Answer 1

Testicular dysfunction
- hormonal causes: Hypothalamic/pituitary disease
- Non-hormonal causes: testicular failure

Not due to testicular dysfunction
- genital tract obstruction
- Abnormal sperm
- erectile/ejaculatory dysfunction

Question 2

Biochemical tests for assessment of male infertility

Answer 2

• plasma testosterone, LH, FSH (gonadotroppins)
• semen analysis (volume, pH, count, motility)
• sperm function & mucous penetration
• anti-sperm auto Aby

Question 3

Biochemical findings of hyPERgonadotrophic hyPOgonadism

Answer 3

Testosterone: Dec
Gonadotrophins: inc FSH or LH
* neg FB working

Question 4

Biochemical findings of hyPOgonadotrophic hyPOgonadism

Answer 4

Testosterone: Dec
Gonadotrophins: N/dec FSH, LH
* neg FB not working

Question 5

Biochemical findings of Primary seminiferous tube failure (i.e. failure of spermatogenesis but Leydig cell function is normal)

Answer 5

Testosterone: N
Gonadotrophins: inc FSH, N LH
* Hi FSH bc fail to secret inhibin

Question 6

Give e.g of disease/syndrome that give rise to hyPERgonadotrophic hyPOgonadism (3)

Answer 6

• Klinefelter’s syndrome (XXY): abnormal seminiferous tubules & testicles
• Acquired teticular defects: due to infection, trauma, Irradiation, drugs
• Aging: declines from age 30

Question 7

Give e.g of disease/syndrome that give rise to hyPOgonadotrophic hyPOgonadism (4)

Answer 7

• Panhypopituitarism: due to pituitary adema, metastasis, surgical trauma, haemochromatostasis
• Hyperprolactinaemia: (dec GnRH secretion) bc pituitary hormone
• Kallmann’s syndrome: defifiency in GnRH bc developmental defect w/ neurons not travellin to right part of hypothal.
• Drugs.

Question 8

Ix of hyPOgonadotrophic hyPOgonadism (3)

Answer 8

• challenge w/ GnRH may be indicated
• Distinguish pitutary vs hypothalamic failure: measure FSH/LH at baseline, 20 & 30 min. if LH not rise by 5U/L = pituitary
• suspect pituitary tumour: asses other pituitary hormone axes

Question 9

Define precocious puberty (PP)

Answer 9

Before puberty:
N: Sn inhibition = low [sex steroids] like GnRH, gonadotropin
PP: Sn is absent = inc secretion of GnRH = LH/FSH released
- caused by: disturbance in hypo/pit axis due to hypothal. lesions, tumours, infections

Question 10

What is pseudoprecocious puberty

Answer 10

Hi sex hormnones bc of:
- gonadal tumour: testis (leydig) or ovary (granulosa)
- Adrenal: CAHyperplasia, Androgen/eostrogen secreting tumours
*but not driven by LH/FSH & sex organs not fully matured = pdeudo

Question 11

Revision: role of LH & FSH in male hormonal axis

Answer 11

LH: acts on Leydig cells = testosterone (androgen) = inhibiting LH (neg FB)
FSH: acts on seminiferous tubule = spermatozoa production & Sertoli cells secrete inhibin = neg FB

Question 12

Compare & contrast 21 hydroxylase & 11 beta hydroxylase deficiency

Answer 12

• Both result in CAH
• elevated ACTH, 17OH progesterone, urine pregnanetriol
• 21: Aldosterone deficiency similar to addison’s = Na wasting
• 11: Hi [ ] 11-deoxycorticosterone (like Aldosterone) = opposite effect as 21 = K wasting

Question 13

Describe the Renin-Angiotensin system for regulation of aldosterone

Answer 13

S: Dec renal blood flow
1. Cells in juxtaglomerular apparatus release Renin (enz)
2. Renin cleaves angiotensinogen to angiotensin I
3. Angiotensin converting enzyme (ACE) cleaves this to Angiotensin II
4. Stimulates secretion of aldosterone from Adr. cortex
R: Na & H2O reabsorption
F: Inc. circulating vol. = -ve feedback