Endocrinological responses to 5-HT.
There is increasing evidence that neuroendocrine and temperature responses in humans can be employed to study the functional sensitivity of different 5-HT receptor subtypes. The evidence suggests that the PRL response to LTP is mediated by 5-HT1 receptors, perhaps the 5-HT1A subtype, though further studies are needed to confirm this effect. It is uncertain whether the PRL responses to other 'presynaptic' challenges of 5-HT function, for example, fenfluramine, are mediated by the same post-synaptic 5-HT receptor subtype as that for LTP. Conversely it seems likely that agonists which stimulate 5-HT2/1C receptors increase both plasma PRL and ACTH in humans. There is also evidence that 5-HT1A receptors can increase ACTH secretion. This suggests that in humans as in animals both the 5-HT1A and 5HT2/1C receptors can facilitate ACTH release, though the significance of this dual control is not understood. It is also possible that both 5-HT1A and 5-HT2/1C receptors stimulate PRL release, but 5-HT1A receptors may have a more prominent role in GH secretion. In both human and animal studies 5-HT1A and 5-HT2 receptor agonists may produce opposite effects on body temperature. These recent developments in 5-HT neuroendocrinology have been of great interest, but much is still uncertain. Progress in this field will be considerably advanced by the availability of new selective 5-HT receptor ligands, particularly selective receptor antagonists.
Cowen
P J
PJ
MRC Clinical Pharmacology Unit, Littlemore Hospital, Oxford, England.
Anderson
I M
IM
Gartside
S E
SE
D000818:Animals; D013006:Growth Hormone / Q000378:metabolism; D006728:Hormones / Q000502:physiology*; D011388:Prolactin / Q000378:metabolism; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000502:physiology*; D014364:Tryptophan / Q000494:pharmacology*
D006728:Hormones; D011985:Receptors, Serotonin; D012701:Serotonin; D014364:Tryptophan; D011388:Prolactin; D013006:Growth Hormone