Insulin-induced hypoglycemia stimulates both adrenaline and noradrenaline release from adrenal medulla in 21-day-old rats.
It has been well-established that insulin-induced hypoglycemia evokes preferential adrenaline release from the adrenal medulla in fasted adult rats. The present study examined the responsiveness to hypoglycemia in fasted 21-day-old and 8-week-old rats. The recovery of adrenaline in the chromaffin granule fraction prepared from the 8-week-old rat adrenal homogenate decreased 30 min after subcutaneous injection of 3 U/kg insulin, whereas the recovery of both adrenaline and noradrenaline was diminished in 21-day-old rats. In electron microscopy, omega-shaped profiles, indicative of exocytosis, were frequently observed in adrenaline- and noradrenaline-storing cells of 21-day-old rats. These results indicate that the responsiveness of the noradrenaline-storing cells to hypoglycemia in 21-day-old rats is different from that in young adult rats.
Fujino
Y
Y
Department of Pharmacology, Teikyo University School of Medicine, Tokyo, Japan.
Fujii
T
T
D000313:Adrenal Medulla / Q000187:drug effects* / Q000378:metabolism* / Q000648:ultrastructure; D000818:Animals; D002838:Chromaffin System / Q000648:ultrastructure; D004837:Epinephrine / Q000378:metabolism*; D007003:Hypoglycemia / Q000145:classification*; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D008854:Microscopy, Electron; D009638:Norepinephrine / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D007328:Insulin; D009638:Norepinephrine; D004837:Epinephrine