Endocrinology, Vol 100, 692-698, Copyright © 1977 by Endocrine Society
Further evidence that serotonin is a neurotransmitter involved in the control of prolactin secretion
JA Clemens, BD Sawyer and B Cerimele
Department of Physiological Research, Lilly Research Laboratories, Indianapolis, Indiana 46206.
Administration of a new specific serotonin uptake inhibitor, fluoxetine,
depressed the firing rate of raphe neurons. A highly significant increase
in serum prolactin levels was observed after ip injection of 30 mg/kg of
5-hydroxytryptophan (5-HTP) in male or female rats pretreated with 10 mg/kg
(ip) of fluoxetine. Neither 5-HTP nor fluoxetine given separately had any
effect on serum prolactin levels. In animals pretreated with methysergide
the combination of fluoxetine and 5-HTP did not increase significantly
serum levels of prolactin. In addition, the serotonin agonist quipazine
elevated significantly serum prolactin levels in male and female rats. The
results of this study strengthen the idea that 5-HTP is acting via
serotonin-containing neurons that influence anterior pituitary prolactin
release, and that serotonin receptor activation leads to prolactin release.
