L20 Hormones and Reproduction

PSB 3340 @ UF Dr. Lori Knackstedt L20 Hormones and Reproductive Behavior

6th

testes and ovaries are undifferentiated until the ___ week of gestation

SRY, testis

the ___ gene on the Y chromosome encodes _____-determining factor

organizational, activational

hormones determine gender via ________ and ________ effects

Wolffian system

system that needs hormones from testes to form; receptors for those hormones must be present; MALE

Mullerian system

the default system (needs no hormonal stimulus from gonads); FEMALE

anti-Mullerian hormone

hormone that causes the Mullerian system to wither away; defeminization

androgens

sex hormones that cause the Wolffian system to develop into the vas deferens, seminal vesicles, and prostate; masculinization

the primordial external genitalia also develop into the penis and scrotum

testosterone

a type of androgen that masculinizes internal sex organs

5a-reductase

enzyme that converts testosterone into the more powerful dihydrotestosterone (DHT), necessary to form male genitalia

gonadotropic hormones

follicle-stimulating hormone (FSH) & luteinizing hormone (LH) are two types of…

gonadotropin-releasing hormone (GnRH)

hormone released from the hypothalamus to the anterior pituitary gland to stimulate the production and release of the gonadotropic hormones

kisspeptin

hypothalamic peptide that simulates the release of GnRH; involved in the onset of puberty

gonadotropin-inhibiting hormone (GnIH)

hormone released by the hypothalamus to inhibit gonadotropic secretion

hypothalamus, GnRH, anterior pituitary, FSH, LH, testes, testosterone, hypothalamus

(MALE) Fill in the blanks using the following: LH, FSH, testosterone, hypothalamus, testes, GnRH, anterior pituitary

__________ → _____ → _______ _______ → ____ & ___ → ______ → ________ → ___________

hypothalamus, GnRH, anterior pituitary, FSH, ovaries, follicle, estrogen, hypothalamus

(FEMALE #1) Fill in the blanks using the following: FSH, estrogen, hypothalamus, follicle, anterior pituitary, GnRH, ovaries

_________ → _____ → ______ _______ → ___ → ______ → _______ → _______ → _________

hypothalamus, GnRH, anterior pituitary, LH, ovaries, ovulation, corpus luteum, progesterone, hypothalamus

(FEMALE #2) Fill in the blanks using the following: LH, anterior pituitary, corpus luteum, hypothalamus, ovulation, progesterone, GnRH, ovaries

______ → ____ → ______ ______ → ___ → _______ → ________ → ______ ______ → ________ → _________

oral contraceptives

pills that contain synthetic steroids which feed back on the hypothalamus and inhibit release of GnRH

hot flashes, memory problems, joint pain, CVD, Alzheimer’s

• symptoms of menopause include….

• menopause also increases the risk of ____ and _______

estrogen, lordosis, testosterone, mounting

female rats injected w/ ______ early in life failed to show _____ as adults; when these same rats are injected w/ ______ in adulthood, they would show ______

aromatase

enzyme that converts testosterone to estradiol

aromatization hypothesis

hypothesis that testosterone enters the brain and is converted there to estrogens, which mascunalize the developing rodent brain

a-fetoprotein

in female rats, estrogen does NOT enter the brain and is kept in the bloodstream where it is bonded with _-________, preventing aromatization and masculinization

rats don’t have enough of these proteins when estrogen is injected → masculinization

medial amygdala, medial preoptic area

the 2 parts of the MALE rat brain involved in sexual behavior are…

sexual, Fos

medial amygdala:

• destruction disrupts _______ behavior

• mating causes production of ____ protein

sexually dimorphic, Fos, testosterone, enhances

medial pre optic area:

• destruction abolishes sexual behavior

• prenatal stress reduces size of ______ ______ nucleus and decreases sexual behavior

• mating causes production of ___ protein

• injection of _______ enhances/disrupts sexual behavior of castrated rats

pheromones

chemical signals that communicate information b/t animals of the same species to help coordinate their reproductive activities

vomeronasal organ (VNO)

organ that has specialized receptor cells near to but separate from the olfactory epithelium and detects pheromones; activates male arousal in rats

olfactory, amygdala, preoptic area

VNO information → accessory _____ bulb → medial ______ → medial ________ ____

proceptivity

female rat’s interest in mating

receptivity

female rat’s willingness to mate

AKA sexually receptive, in heat, estrus

lordosis

position female rat takes to let male know she is receptive

attractiveness

how healthy a mate is; animals know this depending on olfactory cues (hormones)

periaqueductal gray matter, medial amygdala, ventromedial nucleus of hypothalamus

the 3 parts of the FEMALE rate brain involved in sexual behavior are…

Fos, estrogen, progesterone, estradiol, progesterone, enhances

ventromedial nucleus of hypothalamus (VMH):

• destruction abolishes sexual behavior (lordosis)

• mating causes production of ___ protein

• neurons contain _____ and ________ receptors

• injection of _____ and _______ enhances/disrupts sexual behavior of overiectomized rats

estradoil, VMH, increases, estrogen, progesterone

periaqueductal gray matter:

• destruction abolishes sexual behavior (lordosis)

• _____ treatment or stimulation of ___ increases/decreases neural activity

• neurons contain _____ and _______ receptors

medial amygdala

the brain region involved in sexual behavior that is the same in both male and female rats is…

estrogen

important for female proceptive behavior

progesterone

increases proceptive behavior and activates receptivity

ovulation, any

female rats are ONLY receptive during _____ whereas women are receptive at ___ point during their cycle

Persistant Müllerian duct syndrome

genetic disorder:

• there is EITHER no anti-Mullerian hormone OR no receptors for it

• autosomal recessive disorder

• undescended testes and small uterus

• usually infertile, male identity

Androgen Insensitivity Syndrome

genetic disorder:

• lack of androgen receptors prevents masculinization & de-feminizing effects of a androgens

• XY - have testes (internal) and anti-Mullerian hormone

• external sex organs are clitoris and labia

• infertile (no Mullerian system)

• at puberty, breasts develop, hips widen, but no menstruation

Congenital Adrenal Hyperplasia (CAH)

genetic disorder:

• adrenal glands secrete large amounts of androgen → prenatal masculinization

• XY - develop normally

• XX - enlarged clitoris, partly fused labia

• prenatal androgens masculinize the brain

SDN-POA and SBN

2 structures of the brain that are bigger in males are…