Effects of Sex Hormones1 Androgens – INCLUDE Testosterone and DHT○ testosterone → DHT ● androgen produced from testosterone produced through the action of the enzyme 5 alpha reductase, the testosterone gets turned into DHT○ Testosterone ------> Estrogen■ Testosterone can also get turned into estrogen by aromatase■ Defemenizations= taking it away from natures default. Brain and body are defemenized. organizational effect of androgens that prevents the animal from displaying female sexual behavior in adulthood.○ Androgens defemenizationi Estrogen in the hypothalmus is what defemenizes the brain and makes it a male. Yes estrogen (helps the male pattern to develop)○ Congenital adrenal hypoplasia (CAH) leads to homosexuality; condition characterized by hypersecretion of androgens by the adrenal cortex. In females it causes masculination of the external genitiliai Boys born with CAH develop normallyii Females have an enlarged clitoris and labia is partially fused together. Females have an increased chance of becoming homosexual. Excessive androgens affects development of the brain. ● Androgens defemenization organizational (vs. Activational) effectsof the sex hormones○ Organizational (developing breasts, fat storage, large hips, changing permanent structure)○ Activational (periods)2 Distinguish organizational and activational○ Organizational = permanent (effects of sex steroids that are permanent within the brain, body mass). effect of a hormone on tissue differentiation and development Activity of sex hormones with receptors that change physical parts of the body e○ Activational = immediate context – can be reversed if hormone removed (Signals from pituitary that control ovulation-menstrual cycle) occur later in life If you remove sex hormones, the process stops. (spermogenesis & periods)3 AIS (Androgen Insensitivity Syndrome) – genotypically vs phenotypically○ AIS-condition caused by congenital lack of functioning androgen receptors; in a person with XY sex chromosomes causes the development of a female with testesbut no internal sex organs. The cause is a genetic mutation that prevents the formation of functioning androgen receptors, the gene for the androgen receptor islocated on the X chromosome○ XY without functional androgen receptors○ How does the body change?■ Genotypic (ex XY)■ Mutations prevent formation of functional androgen receptors■ (ie receptors for T and DHT)■ T and DHT and Anti-Mullerian hormones are secreted.● Anti-Mullerian: peptide secreted by fetal testes that inhibits the development of female internal sex organs ● Mullerian system: embryonic precursors of the female internal sex organs. ■ T and DHT fail to have their normal organizational masculinizing effects■ Born with external female genetilia■ Gonads are undescended testes, not ovaries■ At puberty, develops a female body○ Know AIS- Genetic males don’t have functional androgen receptors.how does that change the body?■ Since males dont have the receptor they cant masculinize or create the male gentiala. And since the body naturally makes females at puberty she will have have female parts. however she will not have internal female organs because of the anti mullerian hormone. 4 CAH – congenital adrenal hyperplasia (reverse of AIS)○ XX○ High levels of androgens effects phenotypically how?■ In females it causes masculination of the external genitilia■ shallow vigina○ CAH will affect sexual identity in the future (females will be homosexual by being exposed to high levels of )5 Pheromones: a chemical released by 1 animal that affects the behavior or physiology of another animal; usually smelled or tasted and helps carry messages from animal to another○ VNO – vomeronasal organ● is a sensory organ that detects the presence of certain chemicals, especially when a liquid is actively sniffed; mediates the effects of some pheromones. ● VNO is area that registers pheromonal stimuli■ VNO consists of a few hundred sensory receptors positioned near the top of the nasal/sinus passages in most mammals (including humans). VNO sends information to the AOB (accessory olfactory bulb)● AOB is a neural structure located in the MAIN olfactory bulb ■ VNO → AOB → MOB (main olfactory bulb) → Medial Nucleus of Amygdala → POA (Preoptic Area) and Ventromedial Nucleus (VMN) of the Hypothalumus● Hypothalamus detects the pheromone for reproduction■ These are the neural circuits for the effects of pheromones on sexual behavior.● Mammals – pheromones regulate reproductive behavior. In humans, VNO is processed by PRIMARY OLFACTORY SYSTEM○ Know how humans are the exception to the VNO and pheromonal activity (though there is some pheromonal activity in humans) ■ Processed by primary olfactory system■ VNO present but vestigial in humans.■ However, the main olfactory system still appears to register the effects of certain pheromones.■ These differentially influence sex-related behaviors in heterosexual men and women.○ McClintock effect – synchronized cycles in cohabitating women if not on birth control and not around men■ McClintock Effect: Synchronized cycles in cohabitating women● Women cant be on birth control● Coordinate to the more dominate female● A pheromone present in underarm sweat (yuck!) appears to be key.● Extracts from the sweat of men advanced the onset of the next surge in LH (Luteinizing hormone), reduced anxiety and increased relaxation in women. ○ Two compounds in human sweat have differential effects on hetero men and hetero women.These two show how humans feel about sex and potential mates. ■ –Androstadienone (AND) ● AND will make females more aroused ● is an androgenic chemical shown to enhance positive affect and sexual arousal in women but to decrease positive affect in men● Sex steroid hormone that produces pubic and axillary hair and also causes mood in women. ■ –Estratetraene (EST)● will make males more aroused ● is an estrogenic chemical which, in men but not in women, activates hypothalamic nuclei associated with sexual responding.● Maturation of female genitalia; growth of breasts; alterations in fat deposits; growth of uterine lining; inhibition of bone growth; sex drive in women. ○ What Shows pheromonal activity and how men and women find mates?○ Women who aren’t on birth control initiate sex with their partners right around time of ovulation●