PNB 3270 Unit 1

molecular endocrinology

studies of structure, synthesis, and actions of hormones (bioregulators) at cellular and molecular levels

bioregulator

chemicals, non nutrients, intracellular messengers that are effective at micromolar concentrations or less

hormone (traditional definition)

chemical substances produced by specialized tissues (endocrine glands) and secreted into the blood stream, where they are carried to target organs

neurocrines

consist of neurotransmitters and neuromodulators

neurotransmitters

secreted by neurons into synaptic space, include acetylcholine, dopamine, substance P, GABA

neuromodulators

secreted by neurons into synaptic space, modulates sensitivity of post-synaptic cell to other neurotransmitters, includes endorphins and various other neuropeptides

semiochemicals (ectohormones)

secreted into environment, includes allelomones and pheromones

pheremones

secreted into environment, affects same species

allelomones

secreted into environment, affects different species, subdivided into allomones and kairmones

allomones

allelomones that benefit one’s own species, ex. skunk spray

kairmones

allelomones that benefit other species, ex. sweat to mosquitos

neurohormones

secreted by neurons into blood or CSF, includes TRH, CRH, oxytocin, dopamine

hormones

secreted by specialized nonneural cells into the blood, include thyroxine, GH, insulin

cytocrine regulators

secreted by cells into surrounding ECF, local, short distances to target cell, includes somatostatin and norepinephrine, subdivides into paracrine, intracrine, and autocrine receptors

autocrine receptors

signals bind to same cell, include mitogenic agents and interleukins

intracrine receptors

intracellular messengers, typically mediators of other regulators that bind to membrane receptors, includes cAMP, DAG, IP3, cGMP, calmodulin, calcium ions

paracrine regulators

affects other cell types, includes embryonic inducers, somatostatin, interleukins

endocrines

classic hormones secreted into blood

exocrines

secreted into free surface epithelium from exocrine glands, think open tracts

peptides/proteins

chains of amino acids, hydrophilic, most abundant hormone type, includes TRH, GnRH, GH, PRL, insulin, etc.

amino acid derivatives

includes thyroid hormone, epinephrine, some neurotransmitters like glutamate (all derived from tyrosine or tryptophan)

steroid hormones

hormones that are insoluble in water and therefore are transported in the blood via other proteins, includes testosterone, estrogen, cortisone, etc.

lipids

includes prostaglandin, retinoic acid, etc.

nucleotides

includes cAMP, cytokins, 1-methyladenine, etc., hydrophilic

oligosaccarides

short chain carbohydrates

smooth endoplasmic reticulum

steroid secreting cells have a lot of this which provides a hydrophobic lipid environment

ribosomes, rough endoplasmic reticulum, golgi bodies, vescicles

growth hormone secreting cells have a lot of these with aid in transcription and packaging

merocrine secretion

exocytosis, hormone leaves in vesicle

apocrine secretion

sloughing of apical portion of secretory cells, example mammary glands

holocrine secretion

release through cell death and lysis, example sebacceous glands

cytogeneous secretion

release of whole, viable cells, example sperm and ova release

neuroendocrine system

includes hypothalamus and pituitary gland

hypothalamus hormones (hypothalamus releasing hormones)

TRH, GnRH, CRH, GHRH, GH-RIH, PRIH, PRH, MRIH, MRH

pituitary gland hormones (nonglycoprotein tropic hormones)

GH, PRL, ACTH, MSH

pituitary gland hormones (glycoprotein tropic hormones)

TSH, LH, FSH

hypothalamus hormones (neurohormones)

AVP, OXY, endophines, enkephalins

tropic hormones

hormones secreted by pituitary glands that regulate the secretion of hormones from classic endocrine glands

classical endocrine glands

thyroid gland, adrenal gland, gonads, liver

independent endocrine glands

parathyroid glands, thymus, endocrine pancreas, organs of GI tract, pineal gland, kidney

thyroid gland hormones

thyroid hormones T3, T4, calcitonin

adrenal gland hormones (adrenal medulla)

epinephrine and norepinephrine

adrenal gland hormones (adrenal cortex)

aldosterone and corticosterone (cortisol)

ovary hormones

estrogen, progesterone, inhibin

testis hormones

testosterone, other androgens, inhibin

liver hormones

IGF I and IGF II

parathyroid gland hormones

PTH

endocrine pancreas hormones

insulin, glucagon, pancreatic polypeptide, GH-RIH

stomach hormones

gastrin, ghrellin

small intestine hormones

secretin, cck, gastrin releasing peptide, gastric inhibitory peptide, motilin, somatostatin, vasoactive intestinal peptide

pineal gland hormones

melatonin

kidney hormones

erythropoetin, renin, 1,25-dihydrocholecalciferol

endocrine disorders

acromegaly goiter, type I and II diabetes, rickets, Turner’s syndrome, polycystic ovary syndrome

endocrine disrupting compounds (EDCs)

disrupt the activities of endocrine glands or mimic the activities of hormones, disrupts endocrine system, includes insecticides, herbicides, fungicides, industrial or mining byproducts such as heavy metals, dioxins, PCBs, estrogenic or anti androgenic compounds, BPA, etc.