Studies of serotonin function in anorexia nervosa

Area of Science:

• Neuroendocrinology
• Serotonin receptor research
• Eating disorder pathophysiology

Background:

• Serotonergic pathways are implicated in appetite regulation and mood.
• Previous research suggests altered neurotransmitter function in anorexia nervosa (AN).

Purpose of the Study:

• To investigate neuroendocrine, temperature, test-meal, and psychometric responses to serotonergic agents in AN patients.
• To compare responses between low-weight AN patients, weight-restored AN patients, and healthy controls.

Main Methods:

• Administered m-chlorophenylpiperazine (m-CPP), L-tryptophan (L-TRP), and placebo to 12 AN patients and 16 controls.
• Assessed prolactin (PRL), growth hormone (GH), and cortisol (CORT) levels.
• Rechallenged a subset of AN patients after weight restoration.

Main Results:

• AN patients showed blunted PRL responses to m-CPP and L-TRP at both low and goal weights compared to controls.
• Trends for blunted GH responses were observed in low-weight AN patients but normalized with weight gain.
• Cortisol responses, temperature, and test-meal measures were largely unaffected in AN patients.

Conclusions:

• Post-synaptic hypothalamic-pituitary serotonergic pathway responsiveness is altered in AN patients.
• Some neuroendocrine responses showed trends toward normalization after weight restoration, but differences persisted.
• Persistent alterations may indicate central nervous system (CNS) serotonergic changes beyond the hypothalamus.