A circadian rhythm in lipid mobilization which is altered in IDDM.
It is not clear how circadian lipolysis and circulating concentrations of non-esterified fatty acids (NEFA) are altered in intensively treated insulin-dependent diabetic (IDDM) patients. Ten IDDM patients on an intensive insulin regimen and eight healthy control subjects were investigated under ordinary living conditions for 27 h by microdialysis of subcutaneous adipose tissue. The true tissue glycerol concentration and adipose blood flow changes were monitored as an index of lipolysis. A circadian pattern in adipose tissue lipolysis was observed in both groups, decreasing during the day and increasing during evening-night. The daytime decrease was normal, but the evening-night rise was elevated in IDDM (p = 0.03). Circulating NEFA decreased during the day and increased at night. The latter increase was enhanced threefold in IDDM (p = 0.003) and correlated with fasting glucose levels (r = 0.77). Nocturnal growth hormone (GH) was increased fivefold in IDDM and correlated to nocturnal lipolysis (r = 0.83). Adipose tissue blood flow increased during the night in a similar fashion in both groups. Near-normalization of glucose for 24 h in IDDM did not affect the nocturnal increases in NEFA, GH and lipolysis. In conclusion, a circadian rhythm in lipolysis was found. Increased lipolytic rates during evening-night may at least in part raise nocturnal circulating NEFA. Nocturnal NEFA and lipolysis are further enhanced in IDDM, maybe due to elevated GH, but not to insulinopenia or hyperglycaemia.
Hagström-Toft
E
E
Department of Medicine, Huddinge Hospital, Sweden.
Bolinder
J
J
Ungerstedt
U
U
Arner
P
P
D000328:Adult; D000704:Analysis of Variance; D001783:Blood Flow Velocity / Q000502:physiology; D001786:Blood Glucose / Q000378:metabolism; D002940:Circadian Rhythm; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism*; D015314:Dialysis Solutions / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D005990:Glycerol / Q000097:blood; D013006:Growth Hormone / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood; D008053:Lipid Mobilization / Q000502:physiology*; D008066:Lipolysis; D008297:Male; D008875:Middle Aged; D013997:Time Factors
D001786:Blood Glucose; D015314:Dialysis Solutions; D000431:Ethanol; D005230:Fatty Acids, Nonesterified; D006442:Glycated Hemoglobin; D005990:Glycerol; D013006:Growth Hormone; D007328:Insulin