Journal of Clinical Endocrinology & Metabolism, Vol 62, 975-979, Copyright © 1986 by Endocrine Society

ARTICLES

Failure to detect the "dawn phenomenon" in nondiabetic subjects with markedly different patterns of nocturnal growth hormone secretion

N Mauras, AD Rogol and WL Clarke

Overnight serum insulin and plasma glucose concentrations were measured every 20 min from midnight to 0900 h in 13 nondiabetic subjects. Seven were normal men, and 6 had isolated GH deficiency. The pre-breakfast increase in serum insulin concentrations ("dawn phenomenon") did not occur in either group of individuals, and a progressive decline in serum insulin concentrations occurred particularly in the dawn hours (0600-0900 h). The GH secretory patterns were strikingly different in the two groups, with normal spontaneous GH peaks mostly between 0100- 0200 h in the normal subjects vs. virtually flat GH secretion in the isolated GH deficiency group. The absence of the dawn phenomenon in these nondiabetic subjects regardless of their GH secretory pattern suggests that the dawn phenomenon, as described in insulin-dependent diabetic patients, is not an exaggeration of normal circadian rhythmicity in insulin sensitivity.

This article has been cited by other articles:

				R. J. Troisi, C. C. Cowie, and M. I. Harris Diurnal Variation in Fasting Plasma Glucose: Implications for Diagnosis of Diabetes in Patients Examined in the Afternoon JAMA, December 27, 2000; 284(24): 3157 - 3159. [Abstract] [Full Text] [PDF]