ANS 220 Exam 1

What are the types of hormone secretions?

Neurocrine, exocrine, endocrine

What the types of endocrine?

Paracrine, autocrine, and juxacrine

What is nuerocrine secretion?

hypothalamus to posterior pituitary

neurons transport to blood system

What is exocrine secretion?

external

secretion into ducts or onto epithelial surfaces

What are some examples of exocrine secretion?

saliva, sweat, milk, pancreatic enzymes

What is endocrine secretion?

internal

produced in the anterior pituitary and travels via the blood to affect the process in other tissues

What is the classical effect of hormones?

endocrine

What is an example of endocrine secretions?

gonadotropins

What is paracrine secretion?

alters activities in neighboring cells of different cell types

What is an example of paracrine secretion?

theca to granulosa cells

What is autocrine secretion?

alters activities in neighboring cells of the same cell types or secreting cell itself

What is an example of autocrine?

luteal to luteal cells

What is juxacrine secretion?

alters activities in cells immediately adjacent by transmitting directly through components of a cell membrane

What is an example of juxacrine secretion?

luteal to luteal cells

What is a hormone?

substance secreted by a cell that acts on some target cells

What are types of hormones?

proteins, polypeptides, steroids

What concentrations are required for action of hormones?

microgram (10^-6), nanogram (10^-9), picogram (10^-12)

How do we study hormones?

ablation, replacement, isolate and purify hormone, and assay changes

What is ablation?

removal of hormones and studying change in activity

What is replacement of a hormone?

adding the substance back after ablation

What does it mean to isolate and purify the hormone?

study chemical properties

What are the three ways to measure hormones?

Bioassay, radio immunoassay, and enzyme linked immunosorbant assay.

What is a bioassay?

Uses living cell and tissues of the individual to test a response

What is a radioimmunoassay (RIA)?

looking for amount of hormone in the body by using radiolabeled isotope

What is enzyme linked immunosorbent assay (ELISA)?

Uses chemical reactions to determine charge in hormonal concentration

What are the classes of hormones?

non-steroid and steroid

What is the backbone of all steroid hormones?

cholesterol

What are examples of steroid hormones?

adrenocorticoid and sex hormones

What are examples of sex hormones?

testosterone, progesterone, estrogen

What are some chemical properties of steroid hormones?

small, hydrophobic, lipophilic, travels via blood with a carrier, lipid soluble, diffuses through cell membranes, cytoplasmic or nuclear receptor

What is the pathway from cholesterol to progesterone?

27 carbon cholesterol to pregnenolone to progesterone

What steroid takes cholesterol to pregnenolone?

Cytochrome P450 side-chain cleavage or P450scc

What steroid takes pregnenolone to progesterone?

3-beta-hydroxysteroid dehydrogenase or 3beta HSD

What steroid takes testosterone to estrogen?

aromatase

Which process is very slow and has a long duration?

steroid hormones

What is the fate of steroids?

steroids are secreted by gonads - they enter the blood and go to their target tissue - they cause a change in target tissue - steroid in the blood passes to the liver where it is rendered as water-soluble (makes it hydrophilic and lipophobic) - reenters blood and enters kidney or bile - excreted into urine and/or feces as glucronides or sulfates

What are examples of non-steroid hormones?

proteins/peptide hormones, eicosanoids, and biogenic amines and catecholamines

What is an example of a protein/peptide hormone?

oxytocin, FSH, LH

What is an example of a eicosanoid?

prostaglandins

What is an example of a biogenic amine or catecholamine?

melatonin

What are the chemical properties of a non-steroid hormone?

large, hydrophilic, lipophobic, can’t fit through cell membrane, not lipid soluble, received by receptors external to the cell membrane, requires secondary messenger mechanism of action

What occurs in steroid hormone action?

Steroid hormone binds to sex steroid-binding globin and unbinds when they come in contact with their target tissue - passes through the cell membrane because it’s lipophilic - steroid binds to the receptors in the cytoplasm or nucleus of the cell - binds to steroid response element of the DNA - changes the conformation of the DNA which forms mRNA - mRNA is released into the cytoplasm and is taken by ribosomes to make more proteins

What occurs in non-steroid action?

Non-steroid hormone passes through the blood and binds to hormone receptors on the cells membrane - second messenger system (G-protein) is attached to receptor - the binding of hormone to the receptor activates adenylate cyclase on the cell membrane which converts ATP to cAMP - cAMP activates protein kinase in the cytoplasm which activates new protein synthesis

What is the lock and key approah?

describes the interaction between the hormone and its specific receptor

Where are receptors for steroid hormones located?

in the cells cytoplasm or its nucleus

Where are receptors for non-steroid hormones located?

on the cells membrane

What does effectiveness of the hormone depend on?

number of receptors and the affinity of that hormone to its receptor

What is an agonist?

something that looks like a hormone and can bind to its receptor to cause a positive response

What is an antagonist?

something that looks like a hormone and can bind to its receptor to cause a negative response

What does an antagonist do?

shuts down hormone signaling

Which feedback loop is self-regulating?

negative feedback

Which feedback loop is most common?

negative feedback

What is positive feedback?

when a stimulus leads to an increase in the reaction

What is an example of positive feedback?

action of oxytocin on uterine muscle during birth

What is negative feedback?

the primary mechanism through which your endocrine system maintains homeostasis

What causes a stop in positive feedback?

What the stimulus is gone

What causes a stop in negative feedback?

levels of hormones returning back to homeostasis

What is an example of negative feedback?

plasma glucose and insulin response

Where is oxytocin produced?

hypothalamus

Where is oxytocin stored?

posterior pituitary

What type of hormone is oxytocin?

neuropeptide

What signals for the release of oxytocin?

nerves

What are the main functions of oxytocin?

promoting smooth muscle contractions in the uterine wall, the epididymis, and the mammary glands

milk letdown

What is the love/trust hormone?

oxytocin

What type of hormone is GnRH?

neuropeptide

Where is GnRH produced and stored?

hypothalamus

What happens to GnRH in the anterior pituitary?

It stimulates gonadotropes

What does the tonic release of GnRH do?

maintains normal homeostasis

What does the surge release of GnRH do?

causes ovulation in females

The hypothalamus is the ___ hormone while the anterior pituitary is the ___ hormone

releasing, stimulating

What are some examples of releasing hormones?

growth hormone releasing hormone (stimulates growth hormone production/release)

thyrotropin releasing hormone ( stimulates thyrotropin stimulating hormone production/ release)

Corticotropin releasing hormone (stimulates adrenocorticotrophic hormone production/release)

What type of hormone is FSH and LH?

glycoprotein

What produces FSH and LH?

gonadotropins

What does FSH do to the ovaries?

stimulate follicle growth and development and estrogen production

What does FSH do to the testes?

supports Sertoli cell function and estrogen production

What does LH do to the ovaries?

stimulate ovulation and lutenization of the follicles/ progesterone secretion

What does LH do to the testes?

targets leydig cells to stimulate testosterone production

What is the major difference between males and females when it comes to LH?

Produced progesterone in females and testosterone in males

What are the two subunits of FSH and LH?

alpha and beta

Which subunit for FSH and LH provides specificity?

beta

What is the 2 cell, 2 gonadotropin model?

LH binds to LH receptor on the theca cell - ATP is converted to cAMP which creates a pathway to take cholesterol through the mitochondrial membrane to produce progesterone - progesterone goes through a few synthesis steps to make testosterone

FSH binds to FSH receptor on the granulosa cell - ATP is converted to cAMP which releases protein kinase - an increase of aromatase occurs which aromatizes testosterone to estrogen

What are some examples of anterior pituitary hormones?

Somatotropin or Growth Hormone, prolactin, thyroid stimulating hormone, adrenocorticotrophic hormone

What does somatotropin or growth hormone do?

stimulates cell growth, reproduction, and regulation

What is the function of prolactin?

promotes lactation, nest building, and monthly instinct

What is the function of thyroid stimulating hormone?

stimulates T3 and T4 from thyroid

What is the function of adrenocorticotrophic hormone?

stimulates the release of cortisol from the adrenal gland

What type of hormone is testosterone?

steroid hormone

What is testosterone produced by in the testes?

Leydig cells

What is testosterone produced by in the ovary?

theca cells

What does testosterone respond to?

LH surges

Is testosterone negative or positive feedback?

negative

What are the actions of testosterone?

behavioral changes for sexual receptivity and stimulation of anabolic growth

What is the function of testosterone in males?

promotes spermatogenesis, promotes secretion of accessory sex glands

What is the function of testosterone in females?

substrates for estrogen production, masculization

What type of hormone is estrogen?

steroid hormone

What is estrogen secreted by?

sertoli cells in testes, granulosa cells in follicles, and placenta

What does estrogen respond to?

FSH

Does estrogen have negative or positive feedback in females?

both

Does estrogen have negative or positive feedback in males?

negative feedback

What determines positive or negative feedback with estrogen?

If estrogen binds to the tonic center, negative feedback occurs

If estrogen binds to the surge center, positive feedback occurs