This site is 100% ad supported. Please add an exception to adblock for this site.

Endocrinology Exam 1


undefined, object
copy deck
The study of hormones (chemical messengers that travel throughout the bloodstream to transport information fomr one part of the body to another)
Behavioral Endocrinology
The study of how hormones affect behavior and how stimuli, contexts and behaviors affect the release of hormones
Endocrine Communication
Carried out by endocrine cells that release hormones in order to alter the metabolic effects of a targeted cell
What kinds of behaviors can be studied in endocrinology? What are 3 basic quality criteria for these measures
Objective - behavior is directly observed or behavior needs to be inferred Reliable/consistent - can we all agree on what we see and measure? Valid- is it a good index of the phenomenon you want to study?
What methods are available to experimently manipulate hormone
1. administration of hormone (pill/injection/patch) 2. Elimination of hormone-secreting cells in body (castration, ovariectomy) 3. Administer hormone receptor antagonist (a substance that prevents the hormone from binding to its receptors) 4. Genetic manipulation of hormone sensitivity (receptor KO animal model)
Basic Experimental Design!!!
Remove source of hormones (ie. gonads), administer hormone and placebo (oil or sham operation), compare the behavior of the two groups!!
How does Radio ImmunoAssay work?
Add a sample of unknown hormone concentration to a hormone and tracer with a fixed concentration and compare the radioactivity results. - If there is more hormone in the sample, more of the tracer will be displaced, therefore there will be LESS radioactivity *Measure hormones by figuring out how much hormone in sample is displaced by tracer*
Competitive Binding Assay
Both hormone and hormone with tracer compete with each other to bind to antibody - In RIA
How to measure changes in protein?
- Immunocytochemistry: administer a primary antibody that selects for protein of interest. Add a second antibody that will nonspecifically bind to all antibodies. Attach something that will let you visualize the protein - Western Blot: take a section of organ, grind up tissue and put on western blot. is a quantitative analysis of protein
How can you measure changes in mRNA?
In situ hybridization: make a complementary mRNA strand with a radioactive tag attached. If hybridization occurs between both strands, you will be able to see the synthesis of the protein
Sexual Determination
the process by which an organism is originally set up to be a male or female based on sex chromosomes or temperature
Sexual Differentiation
the process during development through which an individual BECOMES male or female by developing differences in brains, bodies, and behaviors due to hormones released by gonads
Hormonal Effects on the development of internal genitalia
- determined by chromosomal sex
Hormonal effects on the development of external genitalia
gonadal hormones determine phenotypic sex. - T + antimullerian hormone cause male phenotype. mullerian duct regresses, wolffian duct masculinzes
Testicular Feminization Mutation
**HORMONAL** - XY, defective androgen receptor on X chromosome
Turner's Syndrome
**CHROMOSOMAL** - XO, female body develops w/ abnormal ovaries
Klinefelter's Syndrome
**CHROMOSOMAL** - XXY, masculine phenotype and develops sterile testes
Congenital Adrenal Hyperplasia
**HORMONAL** - XX, lack enzyme that produces cortisol; therefore, a high amount of androgens. - body is partially masculinized
5 alpha-reductase Deficiency
**HORMONAL** - XY, T not converted into DHT. - INTERSEX genitalia - Usually raised as a female until puberty with rise in androgens so testes descend and penis develops
Research strategies in B.E. 1) Typically lab experiments with animals
change hormone levels experimentally and measure changes in development and behavior
Research strategies in B.E. 2) Typically experiments with animals, humans
Change stimuli/behavior experimentally and measure changes in hormone release
Research strategies in B.E. 3) Typically field studies, studies with humans
measure hormone levels and then measure development and behavior
How hormones may effect behavior?
They do NOT cause behavior. They play a regulatory or permissive role in the emission of behavior!!!
Two functions of the gonads
1. hormones required for development of gametes and secondary sex characteristics 2. hormones necessary for mediating behaviors necessary to bring sperm and egg together **regulated by tropic hormones from the anterior pituitary**
Tract Tracing
Used to map neural circuits to find where degenerating neurons are projecting to - anterograde: soma to terminal buttons - retrograde: terminal buttons to soma
Gonochorism (dioecious)
2 sexes (humans)
one sex - asexual reproduction. Dont pass gametes! technically all females but can produce and fertilize their own eggs
Hermaphrodite (monoecious)
The same individual has both types of gonad and can produce both eggs and sperm
Organizational Effects
The influence of gonadal steriods during CNS development shapes that development and thus has a long lasting effect on male and female organization and behavior. *Relatively permanent, occurs before brain matures, critical period, structural changes in brain*
Activational Effects
Gonadal steriods interact with (or activate) fully developed brain structures to shape behavior. The brain is NOT changed here, but the way it controls behavior is *transitory, occurs in adulthood, no sensitive period, biochemical changes*
Masculinization: Feminization:
M) induction of male traits F) indcution of female traits
Demasculinization: Defeminization:
DM) the removal of the potential for mail traits DF) the removal of the potential for female traits
What is the aromatization hypothesis?
That the estrogen metabolites of testosterone can masculinize the developing brain (T --> E with aromatase) - Alpha feto protein is responsible for binding to mom's estradiol after it crossed the placenta and prevent it from entering fetus' brain. In males, testosterone can cross BBB and be turned into estradiol; therefore the brain is masculinized
3 ways hormones influence the brain to induce sex differences
1. Drive growth of specific brain cells OR prevent death of cells in specific regions 2. Promote outgrowth of dendrites and axons of specific neurons 3. Use a target-derived neurotrophic function: Acts where a neuron synapses. If the synapse survives than the neuron survives *****NEED MORE EXAMPLES******
Describe the evidence for sex differences in the brain
- females have less of a weight difference between R and L hemispheres than men - There is a larger neuronal cell density in langauge related areas of the brain in females than males - the R cortex is more developed in males at 13 weeks gestational age than females - females have a higher cerebral blood flow than males
What is the evidence for the aromatization hypthothesis?
- female rates that develop in between two males are less recepetive and more aggressive as adults due to increased exposure to testosterone - female rats that develop in between other females are more attractive to males than other females due to less exposure to T
Discuss the evidence for sexual differentiation of gender identity in humans
Individuals with congenital adrenal hyperplasia (XX) are usually raised as girls and have a higher incidence of homosexuality and bisexuality. (b/c of more androgens?) ... HOWEVER: no evidence that supports gay men exposed to less androgens than straight men
3 components that characterize female sexual behavior
1. Attractivity - if a female is preferred by a male and if the male is preferred by that female [ 3 chamber prference test : males will prefer female in estrus (receptive) than female in diestrus (nonreceptive)] 2. Proceptivity - initial period in a relationship where organisms court each other. females hop and dart and ear wiggle. E and P are both required 3. Receptivity - in the rat, lordosis. The LQ (lordosis quotient) is the ratio of the # of times the female exhibits lordosis in response to a mount by the male (# L/mounts)
What is pacing?
When a female can escape from a male in a sexual situation. It controls the males mating behavior
What kind of reflex does pacing trigger? What is the ultimate purpose it serves?
The Progestational Reflex!! - vaginal stimulation --> prolactin released from pituitary --> maintenance of CL --> CL produces progesterone --> progesterone helps egg implant. Terminates estrus (receptivity)
Males preference of pacing situation. Females preference of pacing situation
M) shorter intervals and more ejaculations F) longer intervals b/c of pacing to increase implantation of egg and increases probability she'll get pregnant
Spontaneous Ovulation
- Receptivity independent of ovulation: humans, horses - Receptivity occurs only around time of ovulation: rats, mice, primates, dogs, guinea pigs (hormonal control of ovarian development and sexual receptivity)
Induced Ovulation
- ovulation is induced by exogenous stimuli, in particular, the stimulous of mating cats, ferrits, rabits (hormonal control of ovarian development and sexual receptivity)
Environmental inductino of ovarian development and receptivity
voles, parakeets, zebra finches - seasonal breeders: sheep, hampsters
What does estrogen do?
- increases a female's willingness to approach a male - enhances attractivity of the female - primes for progesterone receptors - increases the receptive fields of some sensory nerves
What does progesterone do?
Initial: transient rise stimulates sexual receptivity Prolonged: secretion of P inhibits receptivity because now focuses on maintaining pregnancy
Describe the neural circuitry involved in lordosis....
POA --I VMN ---> Midbrain ---> spine, motor neurons - VMN and estradiol both necessary for lordosis
WHy is estrogen necessary for progesterone to have an effect on reproductive behavior?
Estrogen stimulates production of P receptors within the VMN. P receptors increase lordosis (receptivity). When receptors become saturated the receptivity ends
Roles of T, E, and DHT in male sexual behavior
T: necessary for both motivation and performance. Is able to act on its own but requires E and DHT to masculinize effect E: sexual ability/performance. Stimulates mounting and intro-missions DHT: sexual motivation. Involved in activation of penile reflexes
Brain circuitry in male sexual behavior
Amygdala ---> Bed Nucleus of Stria Terminalis. BNST ---> mPOA A) receives non-contact cues (olfactory). Motivation. # of bar presses decreases BNST) processes chemo-sensory and hormonal signals. motivation. # of non contact erections decreases mPOA) receives contact (tactile) cues and causes mating, hormone release, and sperm production. Ability/Performance. After operation, still would bar press but could not copulate
Human Reproductive Cycle
Follicular Phase (12-14 days): GnRH develops serveral follicles because of FSH. All follicles but one will regress and die and the dominant follicle proceeds to ovulation Periovulatory: (1-2 days) High amounts of estrogen cause a positive feedback and produces an LH surge. Ruptures the follicle and egg is released Luteal: Ruptured follicle turns into corpus luteum and begins secreting progesterone Menstrual: Degenerating corpus luteum causes P and E to decline. Sloughing off of uterine lining that was built up during the luteal phase
Rat Reproductive Cycle
Diestrus I: (2-3 days, similar to follicular phase) Progseterone but not as much Diestrus II: Estrogen and progesterone levels very low Proestrus: (few hours, similar to periovulatory in humans) LH surge Estrus: occurs on day of ovulation. receptivity proceeds ovulation by a few hours
Role of dopamine and serotonin in male sexual behavior
DA: important for locomotion (chasing females), motivation in presence of estrous female, and sensorimotor coordination of mating behavior 5HT: inhibits male sexual behavior (BOTH motivation and performance) it is increased during the post ejaculatory refractory period - Acute cocaine abuse: increase sexual behavior -chronic cocaine abuse: sexual dysfunction and reduced sex drive
Roles of E, P, and A in sexual behavior of primates versus rodents
HUMANS: ovarian hormones NOT necessary for the display of sexual behavior unlike rodents. E and P just influence sexual activity E) increase motivation, vaginal lubrication (night club naked-skin index during ovulatory stage) P) brief exposure facilitates behavior (longterm inhibits behavior) T) secreted right after menstruation and increases sexual desire. RODENTS: E) needed to prime for PR P) needed for receptivity
Associated pattern of reproduction
when the animal produces and releases sper or eggs during the mating season - sexual behavior tied to hormone secretion **rats, guinea pigs, mice, most mammals**
Dissociated pattern of reproduction
when the animal produces and releases sperm or eggs at some time other than during the mating season and stores them until mating occurs - sexual behavior is independent of hormones **Red sided garter snake - stores sperm that was made the previous summer in the epididymus
Constant patterns of reproduction
gonads are maintained continually at or near maximum development. - breed in response to environmental cues - these animals usually live in harsh environments where breedig conditions are completely unpredictable **Zebra Finch in response to rain**
Mixed pattern of reproduction
one sex has an associated pattern and the other sex is dissociated. If the female is associated then the male will store sperm in reproductive tract over to be released when the female ovulates. If the male is associated, then the female mates with the male and stores the sperm in her reproductive tract until eggs are produced at some later time.
How have the environmental and physiological constraints been overcome in the red-sided garter snake?
- hormone manipulation after emergence from hibernation does not affect behavior - dormancy period necessary (at low temperatures) to see male sexual behavior
Diandry and give an example of a diandrous animal
- 2 different male phenotypes - red sided garter snake: He-male and She-male ---> produce female attractiveness pheromone. courted by males in some mating balls. gives competitive advantage in mating ball
female first then turns into a male
male first then turns into a female
4 factors that drive evolution
1. reproductive synergism (behaviors evolved to coordinate hormonal, behavioral, and gonadal events) and reproductive isolation (behaviors evolved to keep species from interbreeding) 2. Natural (traits that are adaptive survive) and sexual selection (when the males compete for the females and the female chooses) 3. constrains on reproduction: environmental (food, temp), developmental (time to produce sperm and eggs) 4. Genetic recombination and phenotypic plasticity: causes individuality
Is sex always determined genetically?
NO - temperature-dependent sexual determination in turtules, alligators, crocidiles, lizards. * Temperature modulates the expression of genes for enzymes and sex steriod hormone receptors ** GECKO: MALE AT 32.5 degrees, FEMALE AT EXTREMES
Is mating always under hormonal control?
NO - animals can rely on proximate cues to activate sexual behavior * environmental: zebra finch starts courtship behavior when rains * chemical stimuli of truffles can cause pigs to begin displaying sexual behavior
Are sex differences in mating always due to differences in brain structures involved in mating?
NO - in the C. uniparins (the parthenogenic whiptail lizard) exhibit both male and female mating behavior in females based on ovarian steroids. - the size of the POA and VMH are identical; however, progesterone actson on POA to initiate mounting behavior when high, and estrogen acts on VMH when high to initiate receptivity ** This behavior is not necessary for reproduction in species but C. uniparens who demonstrate this behavior will lay more clutches and increase reproductive success
Way 1 hormones affect courtship behavior: Activation of systems to produce and receive signals
Female electric fish have knollenorgen receptors that are receptive to T or DHT as is the EOD - T/DHT will broaden EOD of female so like male - T/DHT to male will lower electroreceptor frequency sensitivity **receptors are selective for certain frequencies. males are low, females are high** - correct EOD causes female to oviposit ACTIVATIONAL
Way 2 hormones affect courtship behavior: Masculinize of musculature to organize neural systems
Target-derived trophic effect (not neurotrophic) in frog song - sex differences in development permenantly masculinze or feminize vocal organ. neural pathways sexually dimorphic - The larynx is androgen dependent and needs A to create motor neurons that can contract and relax fast enough to produce song - females cannot generate mating call ORGANIZATIONAL - Estrogen causes female auditory receptors to become more sensitive to call ACTIVATIONAL (low frequency + long time = older, larger adult.. good health)
Way 3 hormones affect courship behavior: Orgainze brain system. 1) neurogenesis/neural survival 2) induce formation of neural connections
In SONG BIRD (left side needed to sing but right can take over if needed) - females have less space devoted to song system then males - hormones act w/ neurotrophic factors during development of song - T increase neuronal survival in males and incorporates these neurons into the song system - new connections could be made off of old projections allowing new songs to be built from old
Measuring sexual motivation
- latency to approach - latency to mount - amount of electrical current the male withstands to reach female - bar pressing - non-contact erections
Measuring sexual ability
- copulatory efficiency (ratio of mounts to intromission) - number of ejaculations - post ejaculatory refractory period (Cooliage effect: PERP gets longer if increase matings with same female, but if you introduce a new female, the male will mate again) - ejaculation latency - inter intromission interval
Kallman's Syndrome
- low levels of testosterone due to GnRH deficiency - do not experience puberty without intervention, so they fail to develop secondary sex characteristics w/o treatment - heterosexual but low sexual drive ** hormone replacement therapy increases sexual interest, spontaneous sexual thoughts and sexual desire ** - T DOES appear to be important for sexual motivation
when young develops within the body of the mother
when the mother lays eggs. the eggs may be ovulated and laid singly or by the thousands
Why is there courtship?
for intra-sexual selection (competition between males). hardiest males have survived to mate and produce offspring

Deck Info