DURATION OF STREPTOZOTOCIN DIABETES INFLUENCES THE RESPONSE OF HYPOTHALAMIC SEROTONIN METABOLISM TO IMMOBILIZATION STRESS
Neuroendocrinology. 1989-01-01; 50(3): 344-350
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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.
(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)
PMID: 2477766 [Indexed for MEDLINE]