Effects of pinealectomy on glucagon responsiveness to hypoglycaemia induced by insulin injections in fed rats.
The glucagon response to insulin-induced hypoglycaemia was tested in rats that had been pinealectomised (Px), pinealectomised and fitted with melatonin implants (Px + MLT), or sham-operated (SO). The glucagon response to hypoglycaemia observed in SO rats (216 +/- 27 pg x ml(-1) at baseline versus 397 +/- 35 pg x ml(-1) at the hypoglycaemic peak, mean +/- S.D.) was stronger than that in Px rats (180 +/- 37 pg x ml(-1) and 229 +/- 21 pg x ml(-1), respectively) and weaker than that in Px + MLT rats (256 +/- 19 pg x ml(-1) and 516 +/- 11 pg x ml(-1), respectively). Our data indicate that the capacity to release glucagon during insulin-induced hypoglycaemia is altered in pinealectomised rats.
Kosa
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Laboratoire des Interactions Fonctionnelles en Neuroendocrinologie, U 501 INSERM, Faculté de Médecine Nord, Boulevard Pierre Dramard, 13916 Marseille Cedex 20, France.
Maurel
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D
Siaud
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P
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002940:Circadian Rhythm; D005934:Glucagon / Q000097:blood / Q000378:metabolism*; D007003:Hypoglycemia / Q000139:chemically induced / Q000378:metabolism*; D007328:Insulin / Q000097:blood / Q000494:pharmacology*; D008297:Male; D008550:Melatonin / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology; D010870:Pineal Gland / Q000502:physiology* / Q000601:surgery; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
D001786:Blood Glucose; D007328:Insulin; D005934:Glucagon; D008550:Melatonin