The role of testosterone Flashcards
What is testosterone?
A steroid hormone that stimulates the development of male secondary sex characteristics
Do females produce testosterone?
Yes but only 10% of the amount that males produce
What is the influence of testosterone on sexual differentiation of a foetus?
Begins early in pregnancy and involves internal and external genitalia as well as the brain and behaviour
What are the gonads?
Sex glands - testes in males and ovaries in females which are genetically identical in XY and XX embryos
What happens in XY individuals?
Genetic information on the Y chromosome causes the gonads to become testes and by week 8 of pregnancy they produce hormones, particularly testosterone
What does the SRY gene on the Y chromosome control?
Whether gonads become ovaries or testes
Who has higher levels of testosterone?
XY have foetuses have higher levels of testosterone than XX foetuses - particularly between 8 and 24 weeks of pregnancy
What happens between 24 weeks of pregnancy and birth?
Gonadal hormone levels are low in both sexes but a surge of testicular hormones after birth makes testosterone once again higher in boys than girls for the first sixth months
What does testosterone do when released?
Causes the development of male sex organs but also acts on the hypothalamus (without this the brains develop as a female type)
What is testosterone often associated with?
With masculinisation of the brain, such as the development of brain areas linked to spatial skills as well as male-type behaviours such as competitiveness and aggressiveness
What are the differences in the hypothalamus of males and females?
The sexual dimorphic nucleus is bigger in males (it is believed that these differences occur through the action of sex hormones, such as testosterone - this is not a universal view though)
What was Young’s research into testosterone?
Gave male hormones to female mice. The effect was an irreversible change in usual gender-related behaviours suggesting that hormones like testosterone have a key role in determining behaviour
What Edward’s research into testosterone?
Found that injections of testosterone in neonate female mice made them act like males with increasing aggression when given testosterone as adults. However control females were only given testosterone as adults and did not react in this way suggesting that testosterone masculinities androgen- sensitive neural circuits underlying aggression in the brain
What was Money and Ehrhardt’s research?
Reported on a sample of girls whose mothers took drugs containing testosterone during pregnancy. The girl exhibited male-type behaviours e.g. playing energetic sports and an absence of female-type behaviours like playing with dolls suggesting that testosterone has a strong influence on gender behaviours.
What was Deady et al’s research?
Measured testosterone levels and gave BSRI to women between 25 and 30 years of age asking additional questions about maternal personality, such as the importance of having children, reproductive ambition and the importance of career. High levels of testosterone negatively correlated with low measures of maternal personality and reproductive ambition suggesting that females’ reproductive drive is affected by testosterone
