13.5 Effects of Gonadal Hormones on Adults Flashcards
what clearly demonstrates he role of gonadal hormones in male sexual behaviour
orchidectomy
what are the two main conclusions from the Bremer study on orchidectomized males?
- reduces sexual interest and behaviour
2. rate and degree of loss are variable
what are the main outcomes of orchidectomy on sexual behaviours (4)
- about half of cases will become asexual within a few weeks
- others can lose their ability to get hard but still have sexual interest and pleasure
- some can still cpulate, but less enthusiastically
- body changes included reduction of body hair on torso, limbs, face, deposition of fat on hips and chest, softening of the skin, reduced muscle mass
how many out of the 102 orchidectomized sex offenders reengaged in sex crimes?
3
why do some males remain sexually active following orchidectomy?
adrenal androgens may play some role - non direct evidence for this tho
what confirms the assumption that the main effects of orchidectomy are associated with the loss of T?
replacement injections of T
describe the case of the man who lost and regained his manhood
castrated in war, soft body w little muscle, wider hips and narrower shoulders, impotent
- T injections
- after 5, and rapid and prolonged erections
after 12 weeks, gained 18 pounds of muscle
- didn’t eliminate his sterility
what are the two widespread assumptions that follow from the necessity of T in male sexual behaviours
are they correct?
- level of a mans sexuality is related to his T levels in blood
- mans sex drive can be increased by increasing levels of T
- NOPE, unrelated in both cases
explain the Grunt and Young experiments on sexual behaviour inn response to T
- rated sexual behaviour of the male guinea pigs in the study
- based on the ratings, grouped them into low, medium, high
- castration, all sex drives fell to negligible within weeks
- recovered after initiation of T replacement
- even tho they all received the same amount, they returned to their old level of sexuality
what is Dihydrotestosterone and why is it interesting
- non aromatizable androgenn
- restores copulatory behaviour in castrated male primates, not in rodents
- indicates that restoration of copulatory behaviour by T has different mechanisms in rodents and primates
- directly due to T in primates
- due to aromatized estradiol in rodents
How long are the gonadal hormone cycles of mature female rats and guinea pigs
describe
4 days
- gradual increase ion estrogen secretion by developing follicles in the 2 days before ovulation
- sudden surge in progesterone as the egg is release
- initiate estrus (12-18 hours when the female is fertile, receptive, proceptive and sexually attractive
what does the close relation between the hormone cycle and estrous cycle indicate about sexual behaviour in female rats and guinea pigs
under the control of hormonal control since sex behaviours match up so well with gonadal hormones
Do the effects of ovariectomy confirm or refute the position that female rodent estrus cycles are determined by gonadal hormone cycles?
- How? (2)
confirms
- ovariectomy produces decline in both receptive and proceptive behaviours
- estrus can be induced in castrated females if you inject estradiol and then progesterone and day and a half later
how are female primates different from rodent and other mammals in terms of the hormonal control of their sexual behaviour?
is this a 100% thing?
only female mammals who are motivated to copulate during periods of non-fertility
what are the three findings that support the view that human primates are still effected by hormonal patterns>?
- more likely to engage in masturbation/ sex
- prefer male faces
- ovariectomy reduces sexual desire and frequency of sexual fantasies
