Reply decided to answer the question "Are changes in mood that may occur during a woman's menstrual cycle caused by biological factors, or are they learned? What evidence supports your response?" from the end of chapter 3. For starters, changes in mood during a woman's menstrual cycle are heavily influenced by biologival factors, but social learning can also play a role. From a biological standpoint, Chapter 3 explains that on the first day of the menstrual cycle, gonadotropin-releasing hormone, also known as GRH, is released from the hypothalamus and it signals the pituitary gland to release lutenizing hormone (LH) and follicle-stimulating hormone (FSH). These hormones regulate estrogen and progesterone levels, which can vary throughout the cycle. Just before menstruation, there is a drop in hormone levels, especially estrogen and progesterone because of the negative feedback loop that is controlled by the hypothalamus, pituitary, and ovaries. These hormonal changes can directly affect brain chemistry and mood