Hormones and Behavior: Key Concepts and Experiments

Arnold Berthold

Studied effects of testes on rooster behavior.

Testes Removal

Caused roosters to exhibit female characteristics.

Testes in Chest Cavity

Resulted in normal rooster behavior.

Frank Beach

Investigated mating behavior in rats.

Testosterone Injection

Rats resumed mating after testosterone administration.

Hormones and Behavior

Journal founded by Frank Beach.

Castration

Surgical removal of testes affecting sexual drive.

Castratis

Castrated men maintaining high voices historically.

Caster Semenya

Athlete barred for high testosterone levels.

Lia Thomas

First NCAA D1 trans athlete winner.

Winner Effect

Testosterone levels change based on sports outcomes.

Endocrine System

System regulating hormones in the body.

Tinbergen's Four Levels

Framework for understanding biological questions.

Proximate Explanations

Focus on how traits emerge and function.

Ultimate Explanations

Focus on why traits evolve and persist.

Bird Song Mechanism

High testosterone in males triggers singing.

Bird Song Function

Singing defends territory and attracts mates.

Developmental Aspect

Young birds learn songs from their fathers.

Evolutionary History of Singing

Songbirds evolved to have singing capabilities.

Behavioral Endocrinology

Study of hormone-behavior interactions.

Hormones

Chemical messengers affecting physiological processes.

Songbird Behavior

Singing affected by hormonal levels.

Chemical messengers

Substances that transmit signals in the body.

Endocrine gland

Gland that secretes hormones into bloodstream.

Target cells

Cells that respond to specific hormones.

Intracrine mediation

Chemical signaling within the same cell.

Autocrine mediation

Cell signals affecting itself.

Paracrine mediation

Cell signals affecting nearby cells.

Endocrine mediation

Hormones traveling through the bloodstream.

Ectocrine mediation

Chemical signals released outside the body.

Exocrine cells

Secrete substances into ducts, not blood.

Endocrine cells

Secrete hormones directly into the bloodstream.

Neural communication

Fast, voluntary signaling between neurons.

Hormonal communication

Slow, involuntary signaling via hormones.

Protein hormones

Large, water-soluble hormones stored in cells.

Steroid hormones

Cholesterol-derived, fat-soluble hormones produced on-site.

Amine hormones

Hormones derived from single amino acids.

Negative feedback

High concentration inhibits hormone production.

Positive feedback

High concentration stimulates more hormone secretion.

Pineal gland

Secretes melatonin, regulates sleep cycles.

Thyroid gland

Produces T3 and T4, regulates metabolism.

Adrenal glands

Release stress and steroid hormones.

Hypothalamus

Regulates pituitary gland hormone release.

Anterior pituitary

Releases hormones into bloodstream, regulated by hypothalamus.

Hormone levels

Influence behavior in dose-dependent or inverted U patterns.

Hormone receptor

Requires specific tissue sample for measurement.

Sensitivity to hormones

Varies among different hormone receptors.

Prairie voles

Exhibit monogamous mating behavior.

Montane voles

Exhibit polygamous mating behavior.

Glucocorticoids

Includes cortisol, corticosterone, and aldosterone.

Androgens

Includes testosterone, DHT, and DHEA.

Estrogens

Includes estrone, estradiol, and estriol.

Progestins

Includes progesterone and allopregnanolone.

Steroid hormone action

Binds to receptors, transcribes DNA into RNA.

mRNA function

Translates to amino acids for protein synthesis.

Estradiol in birds

Binds to receptors, transcribes mRNA for vitellogenin.

Peptide hormones

Include hypothalamic and pancreatic hormones.

GnRH

Gonadotropin-releasing hormone from the hypothalamus.

ACTH

Adrenocorticotropic hormone from the anterior pituitary.

Insulin

Regulates glucose levels in the bloodstream.

G protein-coupled receptors

Activate signaling via G protein upon hormone binding.

Signal transduction

Process of converting hormone binding into cellular response.

Berthold's experiment

Demonstrated testes are transplantable and functional.

Ablation-replacement method

Tests hormone's role by removing and restoring it.

Lordosis behavior

Measured response in females based on hormone levels.

Behavior assessment criteria

Must be objective, reliable, and valid.

CAMP

Secondary messenger produced from ATP during signaling.

Phosphorylation cascade

Series of reactions activated by hormone binding.

Transcription factor

Regulates gene expression in response to hormones.

Hormone Concentrations

Measured in micrograms, nanograms, picograms.

Bioassay

Tests hormone effects on living animals.

Dose Response Curve

Graph showing effect of hormone dosage.

Enzyme Linked Immunosorbent Assay

Common method for accurate hormone measurement.

Direct ELISA

Uses enzyme-conjugated antibodies for detection.

Indirect ELISA

Utilizes secondary antibodies for detection.

Sandwich ELISA

Involves three antibodies for detection.

Competitive ELISA

Measures hormone concentration via competition.

Standard Curve

Plots signal from varying conjugate amounts.

Proportion Measurement

Ratio of labeled to non-labeled hormones.

Chromosomal Sex

Determined by XX or XY chromosomes.

Turner Syndrome

XO chromosomes; develops female but sterile.

Trisomy X

XXX chromosomes; develops female and fertile.

Klinefelter Syndrome

XXY chromosomes; develops male but sterile.

XYY Syndrome

XYY chromosomes; develops male and fertile.

XXYY Syndrome

XXYY chromosomes; develops male but sterile.

De la Chapelle Syndrome

XX with SRY gene; develops male but sterile.

Swyer Syndrome

XY without SRY gene; develops female and sterile.

Gonadal Sex

Identifies presence of testes or ovaries.

Hormonal Sex

Determined by testosterone or estradiol levels.

Freemartin Calves

Sterile female twin shares uterus with male.

Alfred Jost Experiment

Tested hormonal influence on sex differentiation.

Mullerian Ducts

Female ducts that disappear with AMH.

Wolffian Ducts

Male ducts formed by SOX9 and AMH.

SOX9

Protein crucial for male sex determination.

Anti-Mullerian Hormone (AMH)

Hormone that causes mullerian duct regression.

Genital Tubercle

Develops into clitoris or glans penis.

Urogenital Fold

Structure involved in genital development.

Bipotential Genitalia

Initial state of genitalia before differentiation.

Dihydrotestosterone (DHT)

Active form of testosterone for male genitalia.

5 Alpha Reductase

Enzyme converting testosterone to DHT.