ANABOLIC ANDROGENIC HORMONES Flashcards
where is testosterone produced and from what cells where?
testosterone is produced form cholesterol in the Leydig cells in the testes
how do testosterone levels rise and fall in life, what is it bound to? what is it converted to?
testosterone levels rise in the first trimester, during neonatal and then again during puberty.
how do leydig cells produce testosterone using the enzymes
Leydig cells use 5 enzymes: to convert cholesterol to testosterone
20-22 desmolone converts cholesterol to prognenolone
17 a hydroxyls converts pregnenolone to 17 a hydroxypregnenolone
17-20 desmolone converts 17ahydroxypregenolone to DHEA
17B hydroxysteroid dehydrogenase: DHEA to androstenedoil
3B hydroxysteroid dehydrogenase converts androstenedoil to testosterone
control of testosterone synthesis from the hypothalamus
hypothalamus release GnRH which acts on the anterior pituitary which releases FSH and LH which act on the testes
in the testes the leydig cells release testosterone
testosterone can be converted to estradiol by aromatise
testosterone can be converted to DHTby 5a reductase which is more potent and there two proce the androgenic and anabolic effects
how is testosterone bound ?
- 1-2% free
45% SSBG
55- albumin
mechanism of action of testosterone?
testosterone goes through the cell membrane easily because it is lipophillic as its made out cholesterol
once in the cytoplasm it binds to the androgen receptor which is also bound to heatshock proteins 70 and 90
once testosterone binds to AR, they dissociate with the heatshock protiens and enter the nucleus where they join with ARE ( androgen response elements)
then you get activation and transcription process by RNA polymerase 2 which creates new protein
biological effects of testosterone
in foetus testosterone is needed to form the male reproductive tract and external genetilia
during puberty: testosterone promotes the enlargement of the penis, scrotum, facial hair and deeper voice
in adults it retains salt and water, thicker skin , increase sebaceous gland activity, increase in body weight
uses of androgenic steroids
in hypogonadism
andropause
adult male hypogonadism signs, symptoms and diagnosis and causes
signs:
- decreased body hair and muscle mass, small prostate and testes, big breasts, osteoporosis and anaemia
symptoms: depressed, lower libido, tired, infertility, erectile dysfunction
diagnosis:
normal testosterone levels are 300-1000ng/dl
- testosterone lower than 300
- one or more symptom
- positive hypogonadism
what is andropause how is it treated and what are the symptoms ?
andropause is having low testosterone levels which usually happens in older men eg age 65 and older
the changes are slow and subtle and are caused by decreased activity of the Leydig cells.
how does ART work?
-uses derivatives of testosterone to treat the deficit in men
testosterone is ineffective orally as it is inactivated by the liver through coagulation and therefore usually given IM
oral testosterone as ART
oral testosterone HISTERONE
absorption into hepatic circulation
ART side effects, contraindication and cautions
contraindicated in people who have had prostate and breast cancer
cautions:
can increase libido
can cause urine obstructions in the elerly
use with caution in pre pubescent boys as it can stunt their growth
if using IM be wary of bleeding disorders
