all Flashcards
what does a steroid recpetor complex bind to on DNA?
SRE
or promoter
what cell synth steroid in the testis?
leydig
What is the process of T synth in the testis
LH bind LHR on leydig
stimulates the production of T from cholesterol
T diffuse into blood
Sertolic cells have FSHR
FSH bind FSHR stimulate the conversion of T into DNT by 5a reductase
what is the phenotype of an ARKO mouse
testis size 20% of normal
spermatigoenesis arrests at spermatocyte stage
female appearance
how is estradiol made by testis?
androstendione into esterone by aromatase
esterone into 17b estradiol (reversible
androstendione also into T then aromatise
is oestogen imp in testis?
yes ko mice spermatogenesis starts but fails
what occurs in the epididymis?
sperm maturation
what occurs in the seminiferous tubules?
sperm production
what is the purpose of the menstrual cycle?
release of gamete
prepare endometrium for implantation
what are the four phases of menstrual sycle in the uterus
menstrual = failure of imp in last cycle (d1-5) proliferative = repair lining (d5-14) ovulation = release of oocyte (d14) secretory = endo secrete to support implant (d14-28)
What are the two phases of the menstrual cycle in the ovary?
follicular = follicle dev/ovul occurs at end (d1-14 luteal = corpus luteum releases prog (d14-28)
what is an oestrus cycle?
behaviour strategy to ensure mate at ovulation
inc atractiness/recpetiveness/proceptivity
do humans have an oestrus cycle?
attractivness = male prefeer female smell at ovul
receptivity - no ev
proceptivity = dance changes/female tolerate male sweat more near ovul/women isntigate sex more second half of cycle
describe the hormone/brain synthesis
kisspeptin stimulates hypothalmus to produce GnRH
GnrH stimulates the anterior pituitary to relase GN (lh and FSH
these diffuse in blood to gonads
at the ovaries Gn involved in oocyte release and sex steroid synthesis
sex steroid feedback to brain (neg and pos) and also accesory reproductive organs
what is puberty?
individual acquires the beahvioural and physiological attributes to reproduce
what factors infleunce timing of puberty?
genetics is largest factor
stressful events
intra family relationships
endocrine disruption
what evidence is there nutrition afffects initiation of puberty?
japan 1940-70 14-12.5 spanish civil war menarche incr cameroon rural 14.3, urban 13.2 malnutrition/athletes pot critical weigh needed
what evidence is there leptin is important?
increases at start of puberty
KO mice = underdev gonads/ low Gn
treatment reverse abnormalities
what evidence that leptin not the sole signal?
no Leptin receptor on GnRH neurones
what evidence is there Kisspeptin important in puberty?
disrupt the kiss1 gene = infertile
treat rats with Kp = advance time of puberty
is produced in the ARc and AVPV in hypo
its recpetor increases in AVPV at puberty
recpetor expr in GnRH neurone = act GnRH
how does the GPR54 neurone influence transcription
confirmational change reveals a domain Gaq activates Phospholipase C Gas activates adenylate cyclase PLC pathway activates diaglycerol Protein kinase c cascade that activates GnRH transcription plc pathway also release Ca plc also act MAPK mut in rec = delay
what is the link of Kisspeptin and leptin
leptin R on kiss1 neurone
what is the strucute of fsh/lh?
dimeric pr
ab units
b units specific
what are the two isoforms of lh/fsh and why do they form
acidic and basic
post transciriptional mod due to conditions