MT 1 - NPB 152

behavioral endocrinology

what are hormones?

biological signaling molecules

where are hormones secreted into?

blood

what is a role of hormones?

carry to target tissues

what is one thing hormones do?

affect diverse processes (growth, development, physiology, behavior)

what is behavior endocrinology?

effetcs of hormones on behavior and effects on behavior on hormones

What as the study of castration of domesticated animals for at least 2000 yrs?

removed the primary source of testosterone; affected quality as food; affects behavior to be less disruptive socially and more manageable

what is castrati?

castration intended to retain singing voice

what is eunuchs?

castration intended to eliminate sex drive and often serve specific social roles in various cultures.

what is Berthold’s experiment?

A.A Berthold performed first formal behavior endocrinology experiment

demonstrated non-neural contribution by the testes required for normal development of a rooster

concluded that birds w/ transplanted testes entirely normal in appearance and normal behaviorand that testosterone was responsible for these effects.

What are Tinbergen’s 4 questions?

1. How does it develop?

2. What mechanisms cause it?

3. How did it evolve?

4. How does it contribute to survival?

What are the 4 levels of analysis?

The 4 levels of analysis are physiological, ontogenetic, evolutionary, and functional. These levels help in understanding behavior from different perspectives.

What are the developmental mechanisms?

genetic influences on development of behavior

environmental influences on development of behavior

what are the immediate casual mechanisms?

Systems (sensory) for detection of environmental stimuli

Systems (neural/endocrine)for integrating and adjusting responsiveness to stimuli

What are the ULTIMATE causes?

• Historical pathways leading to behavioral trait

  • Evolutionary stages, from origin of trait to present

• Effects of selection on history of trait

  • Effects of past and current usefulness on survival and reproductive success (adaptive function)

    • natural + sexual selection = important

Where are organic molecules produced and released into?

blood by endocrine glands and tissues

What is the main difference between hormones and neurotransmitters?

Hormones are chemical messengers released into the bloodstream by endocrine glands, while neurotransmitters are signaling molecules released by neurons across synapses to communicate with other neurons.

what are 3 interacting components of hormones?

1. input (sensory) systems

2. integrators (CNS)

3. Output systems (effectors)

How do hormones affect different cells?

• target cells possess receptors for specific hormones

• target cells vary in the transduction machinery they possess

• diverse responses to particular hormones possible

how does hormones affect development & expression of behavior?

• Do not cause behavior themselves

• Affect frequency & intensity of expression

• organizational/activational effects

Why do hormones affect fitness?

mechanisms of control affect behavior

what happens in autocrine signaling?

A cell secretes a hormone that binds to receptors on its own surface, influencing its own activity.

what happens in paracrine signaling?

A cell secretes a hormone that binds to receptors on nearby cells, influencing their activity.

what happens in endocrine signaling?

A cell secretes hormones into the bloodstream, which then travel to distant target organs or tissues to exert their effects.

what does neurogenesis mean?

new neurons

what does apoptosis mean?

death of neurons

what does synaptogenesis mean?

new synapses

what does neuritogenesis mean?

new inputs

how do hormones influence the nervous system?

alter membrane potential

neuromodulators

how does the nervous system influence the endocrine system?

neurons secrete hormones - neurohormones

neurons induce endocrine glands to secrete hormones

neurons alter target cell sensitivity

what are the classes of hormones?

steroid

fatty acid derivatives

amino acid derivatives

peptide hormones

what are steroid hormones?

derived from series of enzymatic modifications of cholesterol 

• Androgens, estrogens, progestins

  • Sex hormones

• glucocorticoids & mineralocorticoids

what are fatty acid derivatives?

eicosanoids

what are amino acid derivatives?

thyroid hormone (coupling of two iodinated tyrosines)

amines: epinephrine & norepinephrine, melatonin, dopamine

what are peptide hormones?

Produced by transcription of a hormone gene, translation of mRNA, proteolytic processing & other enzymatic modifications to produce mature peptide hormone

what are the major vertebrate endocrine glands?

pineal gland

hypothalamus

pituitary gland

thyroid gland

parathyroid glands

thymus

adrenal glands

pancreas

ovaries/testes

describe the endocrine glands

• ductless

• rich blood supply

• secrete chemical messengers into bloodstream

• hormones affect only cells that have appropriate receptors

describe the anatomy of hypothalamus pituitary

organized into clusters of neuronal cell bodies

what does neurohypophysis mean?

posterior

what does adenohypophysis mean?

anterior

what are the anterior pituitary hormones?

gonadotropins

thyroid stimulating hormone

adrenocorticotropic hormone

melanocyte stimulating hormone

bendorphin

growth hormone

prolactin

what are the gonadotropins?

luteinizing hormone (LH)

• testosterone synthesis

• induce ovulation

follicle stimulating hormone

• gamete maturation

• estrogen synthesis

what does the thyroid stimulating hormone do?

thyroid gland growth

thyroid hormone synthesis

what does adrenocorticotropic hormone do?

glucocorticoid synthesis by adrenal cortex

behavioral effects too - learning/memory & food uptake

what does the melanocyte stimulating hormone do?

coat, skin, color

what is bendorphin?

endogenous opiods, pain modulatorw

what does the growth hormone do?

somatic cell growht/bone growth via insulin-like growth factor secretion

metabolic effects - glucose, amino acids

What does prolactin do?

lactation

crop milk production (some birds)

freshwater adaptation (migrating fish)

parental care in multiple vertebrate species

water drive - salamander migration

what is the follicle stimulating hormone?

ovarian follicle development in females

sperm production in males

what is the luteinizing hormone?

formation of corpus luteum

ovulation

testosterone production in males

what is the thyroid stimulating hormone?

stimulates thyroid gland

regulate metabolism

what does somatotropic hormone/human growth hormone do?

stimulates protein synthesis

generate growth

what does the adrenocortical hormone do?

help maintain electrolyte homeostasis

cope w/ stress

what does prolactin do?

controls production of milk by breasts

decreases GnRH

inhibits ovulation

what are the posterior pituitary hormones?

Arginine vasopressin

oxytocin

what are the physiological roles of arginine vasopressin?

fluid balance

blood pressure

what are behavioral roles of arginine vasopressin?

pair bonding

what are the physiological roles of oxytocin?

smooth muscle contraction

• mammary gland

• uterus

• male reproductive tracts

what are the behavioral roles of oxytocin?

pair bonding

what are the hypothalamic releasing hormones?

gonadotropin releasing hormone (GnRH)

gonadotropin inhibiting hormone (GnIH)

Kisspeptin

Thyrotropin releasing hormone (TRH)

Corticotropin releasing hormone (CRH)

Somatostatin

Growth hormone releasing hormone (GHRH)

Prolactin inhibiting hormone

what does the Gonadotropin releasing hormone do?

induces gonadotropin secretion (LH and FSH)

what does the Gonadotropin inhibiting hormone (GnIH) do?

opposite of inducing gonadotropin secretion

what does the Kisspeptin do?

activates GnRH - producing neurons

what does the Thyrotropin releasing hormone (TRH) do>

induces TSH secretion

what does the Corticotropin releasing hormone (CRH) do?

induces ACTH secretion

what does somatostatin hormone do?

inhibits GH secretion

what does the Growth hormone releasing hormone (GHRH) do?

induces GH secretion

what does the Prolactin inhibiting hormone do?

inhibits PRL secretion

what does the pineal gland do?

• Secretes melatonin in absence of light

• Inhibits reproductive axis in seasonally breeding mammals

• Influences sleep/wake cycle

what does the thyroid gland do?

has a thyroid hormone from anterior pituitary

what hormones does the adrenal gland do?

catecholamines

adrenal steroids

what are the catecholamines?

• hormones that help the body respond to stress

• released by the adrenal glands and nerve tissue, including the brain

• dopamine, norepinephrine, and epinephrine

where are the adrenal steroids synthesized?

different areas of the adrenal cortex

what are the adrenal steroids?

glucocorticoids (particularly cortisol) in the zona fasciculata (ZF)

androgens and estrogens in the zona reticularis (ZR)

aldosterone in the zona glomerulosa (ZG)

what are androgens?

group of sex hormones that help develop and maintain masculine characteristics

what is progesterone?

hormone that plays a key role in the menstrual cycle and pregnancy

where is progesterone produced?

ovaries, adrenal cortex, and testes

what does progesterone do?

• Prepares the uterus for a fertilized egg to implant

• Inhibits uterine muscle contractions

• Prepares the breasts for milk production

• Prevents changes in the uterus during menopause

• Regulates the menstrual cycle

• Treats amenorrhea (unusual stopping of menstrual periods)

• Decreases the risk of uterine cancer

what are estrogens?

a group of hormones that help develop and regulate the female reproductive system

what does parathyroid glands produce?

parathyroid hormone - calcium balance

what hormone does white adipose tissue have?

leptin - decrease feeding

what hormones are produced in the pancreas?

insulin

glucagon

what does insulin do?

decrease blood glucose

what does glucagon do?

increase blood glucose

what hormones are produced in the stomach/small intestine?

secretin

cholecystokinin

gastrin

multiple other peptides

what does secretin do?

neutralize acid from stomach

what does cholecystokinin do?

induce pancreatic enzymes, bile secretion

what does gastrin do?

stomach secretions

what do hydrophilic hormones do?

Hormones use membrane receptors: amines, peptide hormones

what is an example of hydrophilic hormone?

epinephrinew

what does epinephrine do?

acute stress response leads to reinforcement of sympathetic output as well as elevation of blood glucose levels

what does hydrophilic hormones do?

activate 2nd messenger cascades

• Gets signal across membrane

• Amplifies hormonal signal

• Cross-regulation w/ other signals

can change cell function w/out new protein synthesis

• Cell shape

• Movement

• Ion channel activity 

• Secretion

• Enzyme activity

Can change cell function via new protein synthesis

what are peptides?

short chains of amino acids that are the building blocks of proteins

what are amines?

derivative of ammonia in which one, two, or all three hydrogen atoms are replaced by hydrocarbon groups

what are growth factor receptors?

receptor itself is a tyrosine kinase

what do prolactin/growth hormone/cytokine receptors do?

Receptors activates a receptor associated kinase 

Phosphorylates transcription factors to activate genes

what does lipophilic hormones do?

Primarily use intracellular receptors (nuclear receptors)

Slower acting

Longer lasting effects than hydrophilic hormones

how do hormone levels relate to changes in behavior?

May covary closely, but not always

• Sometimes hormone effects long-lasting

• Some hormones secreted in pulsatile/circadian pattern

• Multiple measurements necessary

Seasonal changes in blood testosterone in male song sparrows

is the hormone necessary for the behavior to be displayed?

If removal of hormone changes, reduces or eliminates the behavior, shows necessity of hormone for behavior

• structural/chemical ablations

• Receptors antagonist - bind receptor & inactivate

Is the hormone SUFFICIENT for the behavior to be displayed?

If replacement of hormone renews behavior, confirms role of hormone in regulating behavior

what are limitations of bioassays?

Expensive

Contaminants

• Can cause false positives or negatives

Need rigorous standardization