Circadian time structure of endocrine and biochemical parameters in adult onset (type II) diabetic patients.

Forty-one endocrine and biochemical serum parameters were studied over a 24-hour span with 6 samples at 4-hour intervals in 20 non-insulin dependent (Type II) diabetics and in 20 non-diabetic subjects matched for sex, age, height and weight. Circadian rhythms were verified by cosinor analysis. Group-synchronized circadian rhythms were detected in diabetic and non-diabetic subjects with no statistically significant difference in any of the rhythm parameters (rhythm adjusted mean, amplitude and acrophase) in: Aldosterone, cortisol, insulin, 17-OH progesterone, prolactin, testosterone, TSH, and in serum albumin, creatine phosphokinase (CPK), serum iron, inorganic phosphate and total protein. Statistically significant (p less than .05) circadian rhythms in both groups with a difference in some parameters between the diabetic and the non-diabetic subjects, which were verified by the Bingham Test (p less than .05) were found with a difference in the mesor in cholesterol, glucose, urea nitrogen (BUN), in the amplitude in C-peptide and in the acrophase in triglycerides, globulin and reverse T3 (rT3). Statistically significant circadian rhythms were detected as a group phenomenon for the diabetics only in progesterone, free and total T4, chloride, calcium, bilirubin and LDH and in the non-diabetic subjects only in ACTH, LH, total T3, alkaline phosphatase, uric acid and potassium. In the remainder of the functions studied, a circadian rhythm was detectable with statistical significance by cosinor analysis as a group phenomenon neither in the diabetics nor in the matched non-diabetic controls (DHEA-S, estradiol, FSH, GH, glucagon, free T3, sodium, GOT and gamma GT). In the absence of a detectable circadian rhythm as group phenomenon, the circadian mean was different between the diabetics and the non-diabetic subjects in sodium, chloride and calcium which were higher in the diabetic patients and serum LDH which was lower. In a comparison of endocrine determinations in the two groups, the circadian mean or mesor in T3 was lower in the diabetics and ACTH higher, without corresponding changes in TSH or in corticosteroids. The circadian time structure of Type II diabetic patients thus seems to be very similar to that seen in non-diabetic subjects of the same sex, age, weight and height. The minor differences found in some rhythm parameters will have to be confirmed or excluded in larger numbers of subjects. The higher circadian mean ACTH concentrations without change in steroid rhythm parameters observed in this group is interesting but will also require confirmation.(ABSTRACT TRUNCATED AT 400 WORDS)

Circadian periodicity of the results of frequently used laboratory tests in elderly subjects.

The circadian rhythms of twenty-one chemical serum parameters (albumin, alkaline phosphatase, calcium, carbon dioxide content, chloride, cholesterol, creatine phosphokinase (CPK), creatinine, glucose, glutamic-oxalacetic transaminase (GOT), gamma glutamyl transferase (Gamma--GT), lactate dehydrogenase (LDH), inorganic phosphorus, iron, potassium, total bilirubin, total protein, sodium, triglycerides, urea nitrogen, uric acid) and of urinary volume and oral temperature were studied, in October 1981, in a group of 49 elderly subjects (23 men, 73 +/- 6 years of age, and 26 women, 77 +/- 8 years of age) institutionalized at the Berceni Hospital for the aged. Statistically significant circadian rhythms as a group phenomenon were found in all functions except alkaline phosphatase, GOT, and LDH. The timing and the extent of these rhythms are presented. The circadian time structure of body chemistry appears well maintained in old age. Some circadian rhythms show a large enough amplitude to require the establishment of time qualified reference ("normal") ranges (e.g. serum iron). In most others, the circadian amplitudes are small and at present of little or no diagnostic importance. They are, however, of physiologic and pathophysiologic interest indicating an intricate time sequence of metabolic events in the human body.