Insulin-induced hypoglycemia elicits thymocyte apoptosis in the rat.
Although various types of stress induce thymus atrophy and suppress immune functions, the mechanisms involved are unknown. To test the hypothesis that thymocyte apoptosis plays a role in stress-induced atrophy of the thymus, we studied the effects of starvation and hypoglycemia on the thymus in the rat. Administration of insulin caused marked hypoglycemia, increased the plasma corticosterone level, and induced fragmentation of thymocyte DNA in fasted but not in fed rats. Administration of either glucose or RU486, a glucocorticoid receptor antagonist, inhibited the apoptosis of thymocytes elicited by insulin. Available evidence suggest that insulin-induced hypoglycemia causes thymocyte apoptosis by promoting glucocorticoid secretion from the adrenal gland.
Morishita
S
S
Department of Biochemistry, Osaka City University Medical School, Japan.
Sato
E F
EF
Takahashi
K
K
Manabe
M
M
Inoue
M
M
D000315:Adrenalectomy; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001284:Atrophy / Q000139:chemically induced; D002478:Cells, Cultured; D053938:DNA Fragmentation; D004305:Dose-Response Relationship, Drug; D006727:Hormone Antagonists / Q000494:pharmacology; D007003:Hypoglycemia / Q000139:chemically induced / Q000473:pathology*; D007004:Hypoglycemic Agents / Q000633:toxicity*; D007165:Immunosuppression Therapy; D007328:Insulin / Q000633:toxicity*; D008297:Male; D015735:Mifepristone / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011965:Receptors, Glucocorticoid / Q000037:antagonists & inhibitors; D013950:Thymus Gland / Q000187:drug effects* / Q000473:pathology
D006727:Hormone Antagonists; D007004:Hypoglycemic Agents; D007328:Insulin; D011965:Receptors, Glucocorticoid; D015735:Mifepristone