secreted by neurons, often enter the bloodstream and act on other organs close or distant

ex: oxytocin, ADH, vasopressin, releaseing hormones

BOTH

can act at synaptic cleft or be released into blood

nervous and endocrine systems are part of a chain, usually synchonizes behavior b/w indivuals

ex. induced ovulation, milking

type of tissue

time

dose

(can change w age, species, type of hormone, disease)

beyond 24 hours and less than one year

ex ovulation

hypothalamus

pituitary

thyroid

parathyroid

pancreas

adrenals

testis

ovary

pineal

heart

intestine

kidney

placenta

endocrine regulation

body temperature

appetite

sex behavior

defense (fear and rage)

activity rhythm

autonomics

adenohypophysis:

pars tuberalis

pars distalis (anterior lobe)

pars intermedia

neurohypophysis:

pars nervosa

neural stalk

secrete MSH and small quantities of ACTH

adenomas can secrete large amt of ACTH and pro-opiomelanocortins, MSH: dark skin

cortex:

glucocorticoid (cortisol)

mineralocorticoids (aldosterone)

sex steroids (minor amts)

medulla:

catecholamines: epinephrine and norepinephrine

corticotropin-releasing hormone

from hypothalamus

stimulates ACTH from pituitary

adrenocorticotropic hormone

from pituitary

stimulates cortisol production from the adrenal cortex

triiodothyronine (T3)

thyroxine (T4)

calcitonin

thyrotropin releasing hormone

from hypothalamus

stimulates TSH from pituitary

thyroid stimulating hormone

from pituitary

stimulates T3 and T4 secretion from thyroid

gonadotropin releasing hormone

from hypothalamus

stimulates FSH and LH secretion from pituitary

follicle stimulating hormone

from pituitary

FEMALE: stimulates follicle development

MALE: stimulates sperm production in the seminiferous tubules

luteinizing hormone

from pituitary

FEMALE: stimulates ovulation and causes the corpus luteum to secrete progesterone during pregnancy

MALE: stimulates testosterone production by the Leydig cells

Growth Hormone Releasing Hormone

from hypothalamus

stimulates GH secretion from pituitary

Growth hormone

from pituitary

stimulates liver to prod IGF-I and IGF-II (somatomedins)

GH by itself also stimulates tissues

Growth Hormone Inhibiting Hormone aka somatostatin

from hypothalamus

inhibits CH secretion by the pituitary when somatomedins are high

Prolactin releasing hormone

from hypothalamus

stimulates prolactin release from the pituitary

from pituitary

stimulates milk secretion

prolactin inhibiting hormone aka dopamine

from hypothalamus

inhibits Pr secretion

from hypothalamus (goes through neurohypophysis)

stimulates milk ejection, uterine contractions, male ejaculation

no negative feedback, short half life

antidiuretic hormone

from hypothalamus

promotes water retention by promoting resorption into the blood from the kidney collecting ducts

stiumalted by high osmotic pressure measured by osmoreceptors in hypothalamus

promotes entry of glucose into muscle and fat cells for metabolic use and storage

calcitriol

1,25-dihydroxycholecalciferol

altered form of vitamin D3 (cholecalciferol)

released from kidneys

stimulates breakdown of bone by osteoclasts and opens gates for calcium to leave bones and enter bloodstream

from kidney

secreted when sodium is low or potassium is high

 forms angiotensin II

hCG

eCG

somatomammotropins

steroids

peptides

growth factors

both fetal and maternal portions secrete hormones

full on or full off

must continuously cycle

usually have a predictable pattern

adjusts output based on demand (deviation from set point)

no cycling and overshooting

offset is an issue (change in load)

prevents offset

small corrective actions when there is a deviation, stops and rechecks, resumes as needed until back to normal

high specificity for ligand

high affinity

ability to saturate (finite binding sites)

binding is reversible

activation causes specific responses

bind hormones that cannot enter the cell

insulin and adrenergic receptors

hormones that can freely enter the cell

steroids and T3 and T4

large molecular size

increased chemical complexity

foreignness

homopolymers that repeat a single amino acid are always poor immunogens despite size

copolymers of only 2 aa can be very active

hormones containing several peptide bonded amino acids are digested and inactivated by gastrointestinal enzymes and microorganisms

all steroid hormones and T3 and T4 can be admin. orally

polypeptides can be damaged by high temperatures

steroids and single amino acid hormones are very stable at high temp

repeated thawing and freezing can harm glycoproteins

t3, t4 and steroid hormones are not different bw species

peptide hormones can bw species

ACTH

MSHs

GH

Pr

Chorionic somatotrophin

FSH

LH

TSH

hCG

eCG

insulin

IGF-1 and IGF-II

relaxin

(glucagon is in the secretin family not insulin family)

cholesterol

pregnenolone

progesterone

aldosterone, cortisol or androgens

acculumated steroids are shunted to androgens leading to virilization

iodine from diet

follicular cell

iodide oxidized by thyroid peroxidase

iodinaton of thyroglobulin

MIT (monoiodotyrosine)

DIT (diiodotyrosine)

2 DIT = T4

mostly in peripheral tissues, MIT + DIT = T3

10% is T3 and 90% is T4

tyrosine from diet

tyrosine hydroxylase -> DOPA (dihydroxyphenylalanine)

DOPA decarboxylase -> dopamine

dopamine-beta-hydroxylase in chromaffin granules -> norepinephrine

cytoplasm phenylethanolamine - N - methyltransferase -> epinephrine

tryptophan

tryptophan hydroxylase -> 5-hydroxytryptophan

serotonin

MAO system -> 5-hydroxyinolacetic acid (inactivated)

in pineal gland:

N-acteyltransferase -> N- acetyl serotonin

melatonin (aka N-acetyl-5-methoxytryptamine)

Goiter

Weight loss (despite appetite)

PPPD

Hypersensitivity to heat

tachycardia

brain

testis

spleen

uterus

(main responsive tissues are muscle and adipose)

lethargy

inactivity

hypersensitivity to cold

probably weight gain from inactivity

PPPD

Pendulous abdomen

Bilateral alopecia

Muscle wasting and weakness