Secretion of glucagon, GLP-1 and GIP may be affected by circadian rhythm in healthy males

BMC Endocrine Disorders

Table 2 Diurnal rhythm of glucagon, GLP-1, GIP, C-peptide and glucose in 24 healthy males

			Output from Cosinor analyses
	Unit	Baseline fasting value Mean (SD)	Mesor (SD)	Amplitude (SD)	Peak, clock time	Cosinor p	Relative amplitude %
Glucagon	pmol/L	3.5 (1.6)	4.2 (0.8)	0.8 (1.2)	18:26	< 0.0001	19
GLP-1	pmol/L	4.0 (1.5)	7.3 (0.2)	2.4 (0.3)	17:28	< 0.0001	33
GIP	pmol/L	4 (2)	49 (2)	45 (3)	18:01	< 0.0001	93
C-peptide	pmol/L	429 (90)	933 (25)	362 (35)	17:59	< 0.0001	39
Glucose	mmol/L	4.8 (0.4)	5.1 (0.04)	0.3 (0.05)	23:26	< 0.0001	6

Data were analyzed with Cosinor analyses, and all five parameters follow a significant diurnal 24-h rhythm (p < 0.0001). N = 22 for the first timepoint (t = 9 h), N = 24 for the remaining 8 time points. Plasma concentrations of C-peptide and glucose were earlier published in [22]. In this analysis a slightly different statistical analysis was performed
Amplitude: half the difference between the highest and lowest value of the fitted cosinor curve, Relative amplitude: 100*(amplitude/mesor). Plasma concentrations of C-peptide and glucose have been published previously [22]
GLP-1 Glucagon-like peptide-1, GIP glucose-dependent insulinotropic polypeptide, Mesor rhythm adjusted average about which oscillation occurs

ISSN: 1472-6823