title: Non-insulin-dependent diabetic patients (NIDDMs) do not demonstrate the dawn phenomenon at presentation.
abstract: A dawn rise of plasma glucose (PG) and/or insulin, the 'dawn phenomenon', has been commonly reported in treated diabetic patients and normal subjects. To evaluate the effect of treatment on this phenomenon in non-insulin-dependent diabetics (NIDDMs), PG, C peptide, immunoreactive insulin (IRI), growth hormone (GH), cortisol, epinephrine, and norepinephrine were measured hourly between 24.00 and 09.00 h in 17 newly diagnosed untreated NIDDMs (group 1). The study was repeated in 11 patients after a year of treatment (group 2). The PG levels did not change significantly at any time from 03.00 to 08.00 h in group 1 but increased continuously from 6.7 +/- 0.5 mmol/l at 04.00 h to 7.8 +/- 0.5 mmol/l at 08.00 h (P less than 0.01) in group 2. IRI and C peptide decreased significantly after 07.00 h in both groups. GH and catecholamine changes were similar in group 1 and group 2. Cortisol levels showed a nadir at 02.00 h and a peak after 07.00 h in both groups. Our results demonstrate no dawn rise of mean PG, IRI and C peptide in newly diagnosed untreated NIDDMs but a significant rise of PG in the early morning period in NIDDMs after a year of treatment with diet alone and diet plus sulphonylureas. Therefore other factors such as treatment and/or duration of the diabetes may play an important role in the pathogenesis of the dawn phenomenon.
mesh_terms: D001786:Blood Glucose / Q000378:metabolism*; D002096:C-Peptide / Q000097:blood; D002940:Circadian Rhythm; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D004837:Epinephrine / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D013006:Growth Hormone / Q000097:blood; D006728:Hormones / Q000097:blood*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood
chemical_list: D001786:Blood Glucose; D002096:C-Peptide; D006728:Hormones; D007328:Insulin; D013006:Growth Hormone; D006854:Hydrocortisone; D009638:Norepinephrine; D004837:Epinephrine