When Karsenty looked at patients with the dense-bones mutation, they had low levels of serotonin in their blood. Osteoporosis patients, though, tend to have normal serotonin levels. Their disease involves not impaired bone formation but accelerated bone loss. Bone is constantly being formed and absorbed, but when the balance shifts toward loss more than formation, the result can be osteoporosis.

Karsenty’s hope is to find a drug that depresses the gut’s serotonin synthesis and stimulates bone growth in these patients. Dr T John Martin, an emeritus professor of medicine at Australia’s University of Melbourne, cautions that all this will take years. He is enthusiastic, though. “This will really change thinking in the field,” Martin said. “It will have a big impact. I’m certain of that.”

Happy hormone

The brain produces over 50 identified drugs, some of which are associated with memory and intelligence.

Serotonin, a hormone manufactured by brain, is a neurotransmitter involved in the transmission of nerve impulses. It is manufactured in body using the amino acid tryptophan. The other n eurotransmitters are dopamine and norepinephrine. At the neurochemical and physiological level, neurotransmitters are extremely important, since they carry impulses between nerve cells.

Serotonin also helps maintain a “happy feeling,” and keeps our mood under control by helping with sleep, calming anxiety, and relieving depression. Hence low Serotonin levels are believed to be the reason for depression which can lead to symptoms like anxiety, apathy, fear, feelings of worthlessness, insomnia and fatigue.