PSB-2000 Lecture Notes - Lecture 11: Hypothalamus, Amygdala, Mammary Gland
Document Summary
Steroid hormones are the type of hormones that consist of 4 rings made of c-carbons. Binds to and activate proteins in cytoplasm. Gonads can produce both types of hormones (aromatase enzyme mediates conversions). Hormonal effects on the brain and genitals occurs in the early stage of development and the effects are long lasting. Examples: injections of androgens in female, or estrogens in male, at early (sensitive) stage may cause masculinization, feminization, and lordosis. The difference in external genitals appearance (female vs. male) stem from gradients of testosterone in early sensitive period. This (cid:662)early sensitive period(cid:663): is short before and after birth in rats and well before birth in humans (3 to 4 months pregnancy). Consists of hormonal effects on the brain and genitals. Occurs in later stage of development any time in life and mediated by testosterone or estradiol. A general rule or tendency in early sexual development: the default tendency of nature is designed mammal for being female.
