Serotonin enhances β-endorphin secretion to lower plasma glucose in streptozotocin-induced diabetic rats
Journal
Life Sciences
Journal Volume
80
Journal Issue
20
Pages
1832-1838
Date Issued
2007
Author(s)
Abstract
Although serotonin, serotonin uptake inhibitors and serotonin precursors (including tryptophan or 5-hydroxytryptophan) are known to have hypoglycemic action in rodents or human, it is not clear whether serotonin has hypoglycemic effect in streptozotocin-induced diabetic rats (STZ-diabetic rats). The aim of this study was to investigate the action of serotonin in regulating the plasma glucose STZ-diabetic rats. Plasma glucose, insulin, β-endorphin and adrenaline were assessed after intraperitoneal administration of serotonin. Serotonin produced hypoglycemic effects without altering plasma insulin and adrenaline levels but increasing β-endorphin level in STZ-diabetic rats. The glycogen content in soleus muscle was increased at 90?min after application of serotonin (0.3?mg/kg) in STZ-diabetic rats. Dihydroergotamine (non-selective 5-HT receptor blocker) and pimozide (5-HT7 receptor blocker) abolished the hypoglycemic effect of serotonin in STZ-diabetic rats. Serotonin-induced hypoglycemic effect in association with the increase of β-endorphin release was abolished in bilaterally adrenalectomized STZ-diabetic rats. In isolated adrenal gland of STZ-diabetic rats, the increase of β-endorphin secretion in response to serotonin was reduced by either dihydroergotamine or pimozide. Pretreatment with naloxone (1.0?mg/kg, i.p.) prevented serotonin-induced plasma glucose lowering effect in STZ-diabetic rats. The results demonstrated that serotonin may activate 5-HT7 receptor on rat adrenal gland to enhance of β-endorphin secretion, which then stimulates the opioid receptor to increase peripheral glucose utilization, resulting in decreased plasma glucose levels in STZ-diabetic rats. ? 2007 Elsevier Inc. All rights reserved.
SDGs
Other Subjects
5 hydroxytryptophan; adrenalin; beta endorphin; dihydroergotamine; glucose; glycogen; insulin; naloxone; opiate receptor; pimozide; serotonin; serotonin 7 receptor; serotonin antagonist; serotonin uptake inhibitor; streptozocin; tryptophan; adrenal gland; adrenalin blood level; animal experiment; animal model; animal tissue; article; controlled study; glucose blood level; glucose utilization; hormone release; hypoglycemia; insulin blood level; male; nonhuman; rat; soleus muscle; streptozocin diabetes; Adrenal Glands; Animals; beta-Endorphin; Blood Glucose; Diabetes Mellitus, Experimental; Epinephrine; Glycogen; Hypoglycemia; Hypoglycemic Agents; Male; Muscle, Skeletal; Naloxone; Narcotic Antagonists; Rats; Rats, Wistar; Serotonin; Serotonin Antagonists; Streptozocin; Rattus; Rodentia
Type
journal article