Untitled Flashcards Set

Hormones and Behavior 

Arnold Berthold (1849) - studied roosters vs hens 

• Do the testes affect behavior in roosters? 

• Those who had their testes removed had the characteristics of females 

• Those who has their testes in the chest cavity were “normal roosters”

Frank beach - work in rats mating behavior 

• Injected rats who stopped mating with testosterone and they continued mating

• Wrote “Hormones and behavior” which became the journal 

Aristotle looked at castration and the effects of it, but did not know why 

Mesopotamia would castrate men so they had no sexual drive and no beard 

19xx’s people castrated were called “castratis’” so they kept their high voice 

Caster Semanya - had incredible amounts of testosterone (hyperandrogenism), and was barred until she could lower her testosterone levels. 

Lia Thomas - Trans athlete in swimming, first NCAA D1 amab trans winner 

World cup italy vs brazil - one team won on a penalty kick, male fans were selected by both sides, and provided saliva samples before and after. Those who had their team won, their test went up, losers test went down - “winner effect” can be applied to the fans as well

1/14/25 

Endocrine system

How to answer questions in biology? Tinburgens four levels 

• Development - how does the trait emerge across the lifespan

• Mechanism - How does the trait work? How is the trait elicited or produced 

• Evolutionary History - How/Why did the trait evolve? 

• Function - Why is the trait adaptive? Why does the trait persist? 

Development & Mechanism are examples of proximate explanations - How?

Evolutionary & function are examples of ultimate explanation - Why?

Why do birds sing?

Mechanism - because they are male and have high testosterone

Function - because they are defending territories that give them access to mates 

Developmental - They learned the song from their father 

Evolutionary history - They are part of the songbird clade, who can all sing 

There are problems with these so we don’t use them mostly

We now focus more on at what time are you looking at for the question 

What is behavioral endocrinology? 

Endocrinology - study of hormones 

Behavior - the study of actions 

Hormones do not produce behavior but they interact with the sensory systems, CNS, and effectors - and everything interacts with each other also 

Example - songbirds - hormones affect behavior

• If testes removed, bird stops singing

• If injected with testosterone singing comes back 

• Singing is most frequent when testosterone is low during mating season

Example Birds - behavior affects hormones 

• When males are challenged testosterone increases

• Challenges must be related to mate access 

What are hormones? Chemical messengers, travel through bloodstream, produced and released by the endocrine gland, act on target cells 

Other kinds of chemical communication - Intracrine mediation, Autocrine mediation, Paracrine mediation, Endocrine mediation, Ectocrine mediation 

Exocrine cells - secrete chemicals into ducts not the bloodstream - salivary glands, digestive glands 

Endocrine cells - travel through bloodstream, most chemicals made by the golgi apparatus, put into a secretory vessel, put into the bloodstream, and connect to a receptor on a target cell 

Neural vs hormonal communication

Neural - close, instant, voluntary

Hormonal - far, slow, involuntary 

Types of hormones 

• Protein hormones

  • Peptide hormones 

  • Large

  • Soluble in blood - no carrier protein necessary 

  • Stored in endocrine cells 

  • Fast acting 

  • Short half-life

• Steroid hormones

  • Small comprised of a cholesterol subunit 

  • Not soluble in blood - must bind to a carrier protein 

  • Not stored - produced on site at the time - can just go through cell membrane 

  • Slow acting - hours to days 

  • Long biological half life 

• Amine hormones 

  • Derived from a single amino acid 

  • Catecholamines - adrenal medulla derived from tyrosine

  • Indole amines - pineal gland 

• Hormone regulation 

  • Negative feedback

    • When the conc is high it will stop production

    • Parathyroid -> parathyroid hormone -> increases Ca2 _> Ca2 stops parathyroid 

  • Positive feedback

    • When conc is high it will secrete more 

    • Female menstrual cycle and the estrogens loop

    • Early cycle - negative

    • Mid cycle - positive 

    • Late cycle - negative 

• Where do hormones come from?

  • Endocrine glands - ductless, rich blood supply, can travel anywhere, can interact with any cell that has the right receptor 

  • Pineal gland - Secretes melatonin, involved in daily and annual rhythms

  • Thyroid and parathyroid - makes T3 & T4, involved with metabolism

  • Adrenal glands - on kidneys, release stress hormones, steroid hormones:

    • Cortex -  Cortisol, Corticosterone, Aldosterone, DHEA 

    • Medulla - Epinephrine, Norepinephrine, dopamine 

  • Pancreas - secrets: glucagon, insulin, somatostatin, pancreatic polypeptide

  • Testes - Strong androgens - DHT, T

  • Ovaries - Estradiol, Estriol, Estrone, Progesterone 

  • Hypothalamus - Regulates the glands through the pituitary gland

    • Corticotropin releasing hormone

    • Gonadotropin releasing hormone

    • Thyrotropin releasing hormone

    • Growth hormones

    • Somatostatin

    • Dopamine

  • Posterior pituitary

    • Contains neurons that produce and secrete peptide hormones

    • Neurons run from hypothalamus to posterior pituitary gland

    • Vasopressin (Antidiuretic hormone), Oxytocin

  • anterior pituitary

    • Neurons in hypothalamus that produce and release hormones 

    • Private bloodstream

      • Hypothalamic pituitary portal system

      • Neurons synapse on primary plexus 

      • Closed one way blood system 

    • Stimulates or inhibits release of anterior pituitary release

    • ACTH, LH, FSH, TSH 

  • Other glands 

    • Thymus, Placenta, Heart, Stomach, Liver, Kidney, Small intestine, skin 

1/16/25 

Why would one animal be more aggressive than another?

• Hormone levels

  • Most we will look at is dose dependent or inverted U 

• Hormone receptor

  • Only way to measure hormone receptors needs a specific tissue sample 

  • The amount of receptors can affect their mono/polygamy 

• Sensitivity to hormones

  • Some receptors are more sensitive than others 

Prairie voles - monogamous 

Montane voles - polygamous

Steroid Hormones

• Glucocorticoids - cortisol, Corticosterone, aldosterone

• Androgens - Testosterone, DHT, DHEA 

• Estrogens - Estrone, Estradiol, estriol

• Progestins - progesterone, allopregnanolone

• Understand the pathways between how it starts as cholesterol and how it gets to what it becomes 

• Actions of steroid hormones 

  • Steroid hormones go through the cell wall and can bind to the receptor

  • This starts its process immediately

  • Hormones receptor complex transcribes DNA into RNA 

  • mRNA translates to amino acids 

  • Steroid hormones lead to changes in gene express over the course of hours or days 

• Steroid example: estradiol in the ovary of a bird 

  • Estradiol binds to the receptor

  • Enters nucleus 

  • Binds to DNA to transcribe mRNA for vitellogenin necessary for protein production 

Peptide hormones

• Hypothalamic hormones (GnRH, GnIH, CRH)

• Antuitary pituitary hormones - (ACTH, LH, FSH, THS)

• Posterior pituitary hormones - (OT, AVP/ADH)

• Pancreatic hormones - (insulin, glucagon, somatostatin)

• Other reproductive hormones (Antimullerian hormones)

• Peptide hormone action

  • Receptors must be in the cell membrane as it can’t go through it 

  • Signal transduction

    • When receptor is bound to, it phosphorylates the g protein

    • This then releases cAMP converted from ATP 

    • MapK -> MapKK -> MapKKK

    • This activates phosphorylase which can break apart glycogen into glucose 

    • mapKKK can activate Creb (transcription factor) which makes phosphetase 

  • Peptide hormone receptors 

    • G protein-coupled receptors (GPCR): Activates intracellular signaling via G protein when the hormone binds, leading to a secondary messenger 

    • Enzyme coupled receptors; have intrinsic enzyme activity, recruits enzyme upon binding, often phosphorylation cascades 

    • Ion channel coupled receptors: opens or closes ion channels in response to hormone binding, altering ion flow and membrane potential

Methods in behavioral Endocrinology 

Berthold's experiment 1849- a group castrated develop as capons, group 2 gets castrated, but reimplanted into the chest of the rooster (normal behavior), group 3 castrated and swapped the testes with another rooster but put them in the proper place (normal male behavior)

• Testes are transplantable organs 

• Transplanted testes still function and produce sperm

• There is no nervous system needed

• Testes produce a “secretory blood born product”

Research strategies in behavioral endocrinology 

• Change hormones and measure behavior

  • Minimally invasive, feeding subjects cortisol laced peanut butter balls 

• Change behavior and measure hormones 

  • Playback experiments can stimulate a behavioral event 

• Measure hormones and measure behavior 

  • Looking for correlations between the two 

How do we measure behavior? 

• Very broad topic, which can conflict between scientists 

• Example

  • Lordosis - if the hormone levels are right, she will arch her back opening her vagina 

  • Measured on a scale from strong to low lordosis 

• Three quality criteria for behavior assessment 

  • Must be objective 

    • Can it be measured without any subjectivity 

  • Is the assessment reliable?

    • Do two observers come up with the same observation

  • Is it valid? 

    • Is the measurement a good index of the phenomenon you want to study

• How do we measure hormones? 

  • Ablation-replacement method

    • Trait should disappear when hormone is removes

    • Adding the hormone back in should restore the trait 

    • Should hormone levels co-vary? 

• How do we measure hormone concentrations 

  • Super low concentrations micrograms, nanograms, picograms

• Bioassay 

  • Test the effects of a hormone on a living animal 

  • Inject known amount of testosterone - measure prostate

    • Dose response curve

    • Effective, but not convenient or sensitive 

• Enzyme linked immunosorbent assay 

  • ELISA 

  • Most common method for measuring hormone levels and accurate

  • Uses enzyme label to produce color change 

  • Direct ELISA 

    • Take unknown sample to a plate 

    • Antibody with enzyme conjugate attaches to hormone antigens

    • This creates color change for detection

  • Indirect ELISA

    • Takes a secondary antibody as its too difficult to get a substrate to bind to the first one 

  • Sandwich ELISA

    • Three Antibodies, two sandwich it and a third secondary 

  • Competitive ELISA 

    • Antibody is labeled

    • Known labeled hormone (conjugate) is added to the solution

    • Sample of unknown conc is added 

    • Labeled antibodies are added to the solutions

    • If equal competitors, they should bind 1:1 

    • More color = less hormones 

    • We make a curve with a bunch of different conjugate amounts 

      • Standard curve 

      • We plot the signal from the different conjugate amounts which gives us our dose-response curve 

      • Proportion to label to non-labeled, because we know how much conjugate we added 

1/23/25 

Peripheral Morphology

What is sex?

• Sex differentiation

  • Chromosomal sex

    • Which chromosomes the specimen has XX, XY 

    • Can be loss, damage or addition of sex chromosomes

      • Turner syndrome - XO sex chromosomes

        • Develop as female but sterile 

      • Trisomy X - XXX 

        • Develop as female fertile

      • Kleinfelters syndrome - XXY

        • Develop as male but sterile

      • XYY syndrome - XYY

        • Develop as male fertile 

      • XXYY syndrome - XXYY

        • Develop as male sterile 

      • De la chapelle syndrome - XX 

        • One of the X’s have SRY (sex Y determining) gene 

        • Male development Sterile 

      • Swyer syndrome - XY

        • Y is missing SRY gene 

        • Female development sterile 

    • SRY activates the testis determining factor TDF (transcription factor)

      • This activates SOX9 expression

      • This makes testicular development

      • In the absence of this, we see ovary development 

      • From here the hormones control it 

  • Gonadal sex

    • What are the gonads: testis or ovaries

    • When in development, the germinal ridge on the mesonephros becomes the gonads - urogenital system

    • Germinal ridge is bipotential at this stage - it can become either male or female gonads 

  • Hormonal sex

    • Levels of testosterone or estradiol 

    • Frank lille - freemartin calves

      • When cows twin ¼ both male, ¼ both female, ½ male and female (female cannot produce milk and is sterile) 

      • Guess - female twin shares uterus with male twin, can this affect the female? 

        • Alfred jost - used rabbits to test this 

          • Removed ovaries from female fetus 

            • Developed as a female infertile

          • Testes removed from male fetus

            • Develops into a female infertile 

        • Alfred jost experiment 2

          • Grafted a teste onto a undifferentiated gonad of a female fetus 

          • Developed into 1 ovary and 1 teste 

          • No substance that changes the development of the female gonad 

          • Grafted a testosterone crystal onto a undifferentiated gonad of a female fetus 

          • Ovary remained an ovary

• Morphological sex

  • Duct system, Genitalia, secondary sex characteristics  - breasts, scrotum etc.

  • Internal organs

    • Ducts -

    • mullerian ducts (female) 

      • No SOX9 no AMH, wolffian ducts disappear 

    • Wolffian ducts (male)

      • SOX9 makes sertoli cells

      • Makes Anti-mullerian hormone AMH

      • This gets rid of the mullerian ducts 

  • External organs 

    • Genital tubercle becomes clitoris or glans

    • Urogenital fold

    • Look at this slide later gotta learn how each develop

    • Genitalia starts bipotential

      • Androgens are necessary for male genitalia

      • Specifically DHT converted from T by 5 alpha reductase

      • Abundant in genital skin 

    • Prader scale

      • If androgens are present during development female will develop ovaries with male genitalia

      • This scale shows the differences in the genitalia

    • DSD

      • Fetal exposure to androgens

        • From self or environment (EDC’s) 

      • 5-alpha reductase deficiency

        • Starts as female but develop male genitalia “guevedoces” 

        • No DHT  

      • Faulty androgen receptors 

        • Androgen insensitivity syndrome (AIS)

        • No androgen receptors 

        • Develop as “hyper” female even with testosterone

          • All female features shown more 

          • Develops testes 

          • AMH makes mullerian system to wither 

          • No period 

        • Partial vs complete 

• Behavioral sex 

  • Brain anatomy 

DSD - differences in sex development 

1/28/25 

Sex differentiation

Behavioral sex

• Sexually dimorphic behaviors 

  • Behaviors that are clearly dimorphic

  • Lordosis (F) - mounting (M)

  • Birdsong - singing (M) - no song (F)

• Classical theory of sexual differentiation 

  • Must be differences in neural behavior 

  • Thought testosterone masculinizes brain, or lack thereof leads to a feminized brain

• Current knowledge of hormones and sex differentiation 

  • Freemartins - sterile female twin of a male means something circulating causes male or female 

  • Prenatal androgens masculinize genitalia - injecting pregnant rats with androgens caused pseudohermaphroditism in XX offspring (ovaries, but external organs are in between) 

  • Basis for organizational differences is neural - ovulating timing is controlled by the hypothalamus not the anterior pituitary gland 

• Guinea pig experiment 

  • Administered T to a pregnant guinea pig and looked at the offspring 

  • Pups allowed to mature and spayed 

  • Female Pups when treated with female sex hormone do not exhibit lordosis

  • When treated with androgens they exhibit mounting (a male behavior) 

• Organizational hormonal action

  • Hormones administered during development can organise the brain to cause permanent changes in behaviors

    • Permanent and irreversible 

    • Must be administered during “critical periods” 

    • Large scale structural changes in neuronal architecture

  • Steroid -> brain -> behavior 

• Activational hormone action

  • Hormones administered to adults can temporarily modify behavior 

    • Temporary and reversible (generally small changes)

    • Only adults 

    • Substrates that hormones act on must be already organized 

    • Brain + Steroid -> behavior 

• Organizational-Activational Hypothesis

  • Differential exposure to hormones early in development organize the neural circuitry underlying sexually dimorphic creatures 

• SNB in the rat

  • Spinal nuclei of the bulbocavernosus are a set of neurons in the spinal cord

  • At birth male and female have the same SNB muscles 

  • Females after birth SNB dies - unless they get a signal to stay 

    • Signal is testosterone 

• Macaque rough-and-tumble play 

  • Juvenile males play more than females in all ways 

  • Has to be organizations as they’re juveniles 

  • We see sex differences so we can assume its organized 

• African clawed frog

  • Male and female have sexually dimorphic vocalizations 

  • If female is given test they will start the male sound 

  • Activated only as its already organized 

• Canid (Dog) urinary posture

  • Sexually dimorphic urinary positions 

  • Females squat while males lift their leg to pee 

  • Males start from squatting and develop lifting their leg

  • Both organized and activated 

• How do we know if the brain is organized 

  • Identify dimorphic behavior 

  • Identify dimorphic hormones during development & adulthood 

  • Identify dimorphic brain morphology or neural morphology 

• Spinal nucleus of the bulbocavernosus (SNB) more prevalent in males than females  

• The aromatization hypothesis

  • T enters brain, can flow through blood brain barrier

  • Contacts aromatase (converts testosterone to estradiol) 

  • E2 binds to Estrogen receptors

  • ER changes gene expression to masculinize stuff 

  • Estrogens alone can cause masculinization 

• The protection hypothesis

  • Alpha fetal proteins protect from masculinization

  • Stops the estrogen before crossing the blood brain barrier 

  • T can still get aromatized 

  • Mostly protects against maternal estrogen masculinizing the fetus 

• Primates do not act the same (humans and primates) 

  • They are not masculinized organizationally by estradiol 

  • Primates

    • Masculinized by androgens (testosterone)

    • Mediated directly by androgen receptors 

• Re-examining the hormonal theory

  • Goat breeders noticed male goats do not develop horns and are less fertile

  • Goats were XX 

  • These goats have a damaged determining factor (FOXL2) so they developed as mostly male 

• In presence of Y chromosomes

  • More vasopressin fibers in lateral septum 

  • More dopaminergic neuron in midbrain

  • Higher aggression

  • Lower parental behavior

• In absence of Y chromosome

  • More likely to develop addiction

  • Lower aggression 

  • Higher parental behavior 

• Fish sex determination 

  • Gonochoristic fish - an individual remains the same sex throughout their life

    • XX - XY but use DMY as a sex determining gene

  • Sequential hermaphroditism - start as one and end as another 

    • You want to be the sex that can produce the most offspring for you

    • Protogyny - female to male 

      • Most common form in nature 

      • Biggest fish in the whole group is the dominant male 

      • If dominant male is removed next biggest fish becomes dominant male regardless of gender 

    • Protandry - male to female 

      • Largest fish are the dominant breeders 

  • Simultaneous hermaphroditism - both at the same time 

    • Ovotestes produces both eggs and sperm 

    • They take turns producing eggs and sperm to make sure that they are being fair with the egg/sperm production

2/4/25 

review 

lillie, jost, berthold, phoenix et al should be known