Serotonin and Estrogen Levels Found Linked
This entry was posted on 5/16/2006 8:48 PM and is filed under Healthy Aging.
Serotonin, a neurotransmitter, also functions as a hormone which allows it to cause effects in the body outside of the nervous system. Fluctuations in estrogen levels in women are found to cause predictable changes in serotonin systems. Scientists now believe that serotonin may mediate the effects of estrogen. In the CNS (Central Nervous System), estrogen influences pain transmission, headache, dizziness, nausea and depression all of which are known consequences of serotonergic signaling. Outside of the CNS, estrogen produces changes in bone density, vascular function and immune function that are also consistent with effects of serotonin.
Only 1% of serotonin in the human body is found in the CNS, with 99% found in other tissues such as plasma, GI (gastro-intestinal) tract and immune tissues. Here serotonin functions as a hormone and regulates physiological functions such as vasodilation, clotting, immune cell recruitment, and GI motility. It is also involved in bone density as is estrogen.
Changes in estrogen levels (specifically E2 or estradiol) influence concentrations and actions of serotonin as well as modulating the actions of serotonin. For example, the loss of estrogen at menopause results in decreased density of 5HT (precursor of serotonin) receptors and lower activity of serotonin, which could explain aberrant temperature regulation, including hot flashes and night sweats. Prevalence of hot flashes and sweating at night could be the result of conversion of serotonin to melatonin at night, resulting in lower circulating serotonin levels.
Depression in women is often found increased during times of relatively low estrogen levels (early pregnancy, postpartum, peri-menopapuse and menopause) and this may be at least partially due to estrogen's effect on serotonin receptors.
As reported in Medscape 4/06/2006: An Overlooked Connection: Serotonergic Mediation of Estrogen-Related Physiology and Pathology. Leszek A. Rybaczyk; Meredith J. Bashaw; dorothy R. pathak; Scott M. Moody; Roger M. Gilders; Donald L. Holzschu
