The Debate Over the Cause of Weight Gain in Menopause
SevEαl theories have been advanced to explain the cause of weight gain at the time of menopause. Some scientists have attributed it to a decrease in thyroid function, with a subsequently decreased metabolic rate. With lowered metabolism, fewer calories are required to maintain current weight, and if caloric intake remains the same, then weight will increase. Another theory is that the weight gain is due to age-related decreases in muscle mass. Because muscle tissue burns more fuel than fat tissue, a disproportionate loss of muscle mass can result in a reduced requirement for calories. Consequently, maintenance of the same caloric intake will again result in increased body weight. However, some scientists believe the weight gain that occurs at menopause may in fact be due to the reduced production of the female sex steroid estrogen that occurs at the time of menopause.
Proponents of the "estrogen argument" point to data from clinical and animal experiments indicating that estrogen is an important modulator of food intake and body weight. Scientists, who commonly study rats that have had their ovaries removed (ovariectomized [OVX] rats) in order to mimic the decline in sex steroids that occurs at menopause, have found that OVX rats eat more and gain weight more rapidly than sham-opEαted control rats. Estrogen replacement reduces both the increased food intake and the body weight gain of the OVX rats.
The Role of Estrogen Receptors Eα and ER
Sex steroids such as estrogen induce actions by binding to a receptor. The two subtypes of estrogen receptor are Eα and ER. However, the role of each subtype in the effects of es
Contact: Donna Krupa
American Physiological Society