DURATION OF STREPTOZOTOCIN DIABETES INFLUENCES THE RESPONSE OF HYPOTHALAMIC SEROTONIN METABOLISM TO IMMOBILIZATION STRESS
Neuroendocrinology. 1989-01-01; 50(3): 344-350
DOI: 10.1159/000125244
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1. Neuroendocrinology. 1989 Sep;50(3):344-50.
Duration of streptozotocin diabetes influences the response of hypothalamic
serotonin metabolism to immobilization stress.
Chaouloff F(1), Laude D, Mérino D, Serrurier B, Baudrie V, Elghozi JL.
Author information:
(1)Laboratoire de Pharmacologie, INSERM U7, CHU Necker, Paris, France.
Neurochemical and metabolic effects of acute (immobilization for 2 h) and chronic
(immobilization for 2 h/day for 4 consecutive days) stress were investigated in
diabetic female rats either pretreated 1 week or 5 weeks earlier with
streptozotocin (STZ). Hypothalamic serotonin (5-hydroxytryptamine, 5-HT)
metabolism was estimated by measuring the respective levels of 5-HT precursor,
the amino acid tryptophan (TRP), 5-HT and the 5-HT metabolite, namely
5-hydroxyindoleacetic acid (5-HIAA). To assess the respective metabolic effects
of stress and diabetes, plasma total TRP, insulin, glucose and corticosterone
levels were measured. Short- and long-term STZ treatment triggered marked
decreases in plasma total TRP and hypothalamus TRP levels but the diabetogenic
agent diminished 5-HT metabolism in the 1-week ST-treated rats only. Acute stress
promoted a marked decrease in plasma total TRP in the vehicle-treated rats and in
the 1-week-diabetic rats, which was associated with significant increases in
hypothalamic TRP and 5-HIAA levels. In the 5-week-diabetic rats, a single
restraint affected neither peripheral and central TRP levels nor hypothalamus
5-HT metabolism. Acute stress triggered hypercorticosteronemia in all groups of
rats but it promoted hyperglycemia and hypoinsulinemia in the vehicle-injected
rats only. Twenty-four hours after the fourth immobilization, plasma total TRP
was reduced in the vehicle-injected rats only with no effect on hypothalamic
levels of TRP. On the other hand, chronic restraint was found to reduce
exclusively hypothalamus 5-HT and 5-HIAA levels in the 5-week-diabetic
rats.(ABSTRACT TRUNCATED AT 250 WORDS)
DOI: 10.1159/000125244
PMID: 2477766 [Indexed for MEDLINE]