HPG axis Flashcards
what does the HPG axis consist of?
hypothalamus, anterior pituitary, testes/ovaries
what does the hypothalamus regulate?
metabolism, growth reproduction, stress
what does the hypothalamus secrete?
gonadotrophic releasing hormone
what are the different groups of cells that make up the anterior pituitary?
thyrotropes, somatotropes, gonadotrophs, cortiotrpes, cactotropes
how does GnRH influence the gondatrophs?
causes proliferation and FSH and LH hormone production
3 main types of sex steroid hormones
progestagens,androgens, oestrogens
what precursor are all steroids derived from?
cholesterol
what hormones exert a depressant effect on gonadotrophin output?
oestrogens and progestogens, inhbins
what hormones positive regulate gonadotrophins?
activin and oestrodiol at high concentrations
what does oestrogen do at low levels?
negatively regulates LH expression
where do oestrogens and progestagens act?
on the hypothalamus or directly on the pituitary
what are the two types of cells present in developing follicles?
granulosa and thecal cells
what is absent in male HPG regulation?
positive feedback
what cells secrete androgens?
leydig
what cell types do males have in the developing follicles?
sertoli and leydig cells
