Endocrninology Flashcards
how does the endocrine system work
uses blood circulation to transport hormones and signals
steps for endocrine communication
-chemical messenger
-secreted by endocrine glands
-transported by blood
-target tissue-physiologic response
father of endocrinology
Berthold-castration experiment
explain Berthold’s castration experiment and what conclusion was drawn from it
he had three groups
-group 1: castrated–>lack of secondary sex characteristics
-group 2: castration then reimplantation–>normal male development
-group 3: castration and transplantation–>normal male development
-the study proved that testes were the gonad and produced something that led to secondary sex characteristics
ablation definition
remove and study change in activity
isolate and purify hormones definition
allows you to study chemical properties of hormones
replacement definition
after ablation, add substance back
assay definition
allows you to measure concentration of something
radioimmunoassay
place isotope^125 and sample in with the antibody of the hormone you’re measuring
(higher radiation=lower concentration)
ELISA assay
sandwich desired hormone between 2 antibodies which causes a change in color, the deeper the color the higher the concentration
types of secretion
-endocrine
-paracrine
-autocrine
-intracrine
-lactocrine
-pherocrine
endocrine definition
uses bloodstream
paracrine definition
hormone stimulates adjacent cell w/out entering bloodstream
autocrine definition
hormone stimulates same cell that secretes the hormone
intracrine definition
hormone stimulates the cell without being secreted
lactocrine
molecules can be in colostrum that can effect organ development in offspring
pherocrine
chemical messenger that communicates from one animal to another
flehmen response
moving lip to expose vomeronasal organ to recieve pharemones
examples of positive feedback
-oxytocin on uterine muscles during birth
-estrogen on ovulation
what stops positive feedback loop
when action hormones were building to occur
what hypothalamic center is positive feedback connected to
the surge center/preoptic area
what hypothalamic center is negative feedback connected to
the tonic center/arcuit center
what neuron is required for steroid reception? why?
kisspeptin. GnRH neurons dont have steroid receptors
agonist vs. antagonist
agonist-binds to receptor and elicits same response as endogenous hormone
antagonist-binds to receptor to block endogenous hormone
chemical structure of protein hormones
amino acid chains
chemical backbone of prostaglandins
arachidonic acid(PUFA)
chemical backbone of steroid hormones
cholesterol
sex steroid hormones
-testosterone
-progesterone
-estrogen
what enzyme turns cholesterol into pregnenolone
cytochrome p450 side chain cleavage
what enzyme turns pregnenolone into progesterone
17-β-hydroxysteroid dehydrogenase
what enzyme turns testosterone into estrogen
aromatase
what 2 enzymes convert androstenedione–>testosterone or estrone–>estrogen
aromatase and 17 β hydroxysteroid dehydrogenase
T/F proteins can circulate freely in the bloodstream, why/why not?
True, they are hydrophilic
protein hormone response pathway
non soluble through lipid bilayer so hormone attaches to primary receptor. this activates the coupled G-protein to activate adenylate cyclase. adenylate cyclase converts ATP–>cAMP(secondary messenger). cAMP activates protein kinase. kinase interacts with DNA synthesis leading to desired response.
why do steroid hormones need a carrier to travel in blood
they are hydrophobic/lipophelic
2 main steroid hormone carriers
-sex hormone-binding globulin(SHBG)
-sex steroid-binding globulin(SSBG)
steroid hormone response pathway
hormone passes through cell membrane and binds to receptor within nucleus. hormone/receptor travel to SRE(regulating element of DNA). it travels to mRNA for transcription and translation to create desired response.
protein hormone metabolism
metabolized in liver
-bonds are broken to turn it into a glycoprotein
-glycoprotein excreted in urine
where does prostaglandin metabolism occur
in the lungs
metabolization of PGF2A by cows vs horses? why important?
cow: 80-90%
horse: 20%
what they can metabolize impacts dosage
steroid hormone metabolism
-in the liver double bonds are removed and a glucuronic acid/sulfate group is added rendering it water soluble
-it travels to kidneys and is excreted in urine
GnRH
producing gland:
hormone type:
function:
-hypothalamus
-peptide
-stimulate release of FSH and LH from anterior pituitary
dopamine
producing gland:
hormone type:
function:
-hypothalamus
-peptide
-inhibit release of prolactin
corticotropic releasing hormone(CRH)
producing gland:
hormone type:
function:
-hypothalamus
-peptide
-stimulate ACTH release
growth hormone releasing hormone(GRH)
producing gland:
hormone type:
function:
-hypothalamus
-peptide
-stimulate release of growth hormone
oxytocin
producing gland:
hormone type:
function:
-hypothalamus(released by posterior pituitary)
-peptide
-contractions for sperm transport/parturition, milk let down
FSH
producing gland:
hormone type:
function:
-anterior pituitary
-protein
-stimulate follicular growth and sex steroid hormones(estrogen and testosterone)
luteinizing hormone(LH)
producing gland:
hormone type:
function:
-anterior pituitary
-protein
-stimulate ovulation in females and testosterone synthesis in males
prolactin
producing gland:
hormone type:
function:
-anterior pituitary
-protein
-stimulate milk synthesis and effect maternal behavior
growth hormone(somatotropin)
producing gland:
hormone type:
function:
-anterior pituitary
-protein
-stimulate milk synthesis
adrenalcorticotropic hormone
producing gland:
hormone type:
function:
-anterior pituitary
-protein
-release of corticosteroids, initiate parturition
estrogen
producing gland:
hormone type:
function:
-ovary(graafian follicle)
-steroid
-secondary sex characteristics
progesterone
producing gland:
hormone type:
function:
-Corpus Luteum
-steroid
-Maintenance for pregnancy, control follicular growth
inhibin(Female)
producing gland:
hormone type:
function:
-graafian follicle
-protein
-regulate release of FSH
relaxin
producing gland:
hormone type:
function:
-corpus luteum and palcenta
-protein
-expansion of pelvis during parturition
androgens-testosterone
producing gland:
hormone type:
function:
-testis(leydig cells)
-steroid
-male mating behavior, spermatogenesis
inhibin(male)
producing gland:
hormone type:
function:
-Sertoli cells
-protein
-regulate release of FSH
cortisol(glucocorticoids)
producing gland:
hormone type:
function:
-adrenal cortex
-steroid
-induce parturition
human chorionic gonadotropin
producing gland:
hormone type:
function:
-placenta
-glycoprotein
-support CL(like LH)
equine chorionic gonadotropin
producing gland:
hormone type:
function:
-placenta
-glycoprotein
-immunological protection during pregnancy(like FSH)
estrogen/progesterone
producing gland:(placenta)
hormone type:
function:
-placenta
-steroid
-regulate placental blood flow
placental lactogen
producing gland:(placenta)
hormone type:
function:
-placenta
-protein
-stimulate mammary growth
prostaglandin F2A
producing gland:
hormone type:
function:
-uterus endometrium
-lipid
-regression of CL
prostaglandin E2
producing gland:
hormone type:
function:
-Graafian follicle
-lipid
-ovulation, sperm transport
insulin-like growth factors
producing gland:
hormone type:
function:
-liver
-protein
-stimulate mammary growth and fetal developement
melatonin
producing gland:
hormone type:
function:
-pineal gland
-amine
-controle seasonal reproduction
