Detailed information on adrenal function in autoimmune Type 1 diabetes with onset in adult age is still missing. This work compared diabetics with low response (LR) to diabetics with normal response (NR) to low dose ACTH test and control group (C).
Thirty-two diabetics were investigated; LR (n=16), NR (n=16), age 44±10 years (mean±S.D.), age at diagnosis 28.5±10 years, disease duration 15±8 years, BMI 24.5±2.7 kg/cm2, HbA1c 7.2±1.2%. Control group consisted of 16 healthy subjects; age 27±6 years, BMI 21.7±2.3 kg/cm2. Neither group showed any clinical signs of adrenal disorders or adrenal laboratory autoimmunity. The study was approved by local Ethical Committee. Adrenal reserve was tested by low dose ACTH test. Adrenal autoantibodies, plasma renin activity, transcortin (CBG) were determined. Diurnal rhythm of salivary cortisol was investigated at 8 am, 12 am, 5 pm and 10 pm.
Basal and stimulated serum and salivary cortisol levels in NR did not differ significantly from those in C. Diurnal rhythm of salivary cortisol in NR did not differ from C. In LR, basal and stimulated levels of serum and salivary cortisol were significantly lower than C and NR, P<0.001 for all times. Diurnal rhythm was changed, the levels of salivary cortisol were lower than NR and C, at 8 am and at 12 am P<0.05. LR did not differ from NR and C in either basal ACTH value, or basal plasma renin activity, but levels of CBG was significantly lower than NR, P<0.005.
In conclusion, low response to low dose ACHT test was associated with changes in diurnal rhythm of salivary cortisol and lower levels of CBG. These changes support the conclusion that a portion of diabetics even without adrenal autoimmunity show adrenal function impairment. The clinical significance remains to be evaluated. The study was supported by grant No.NR/9154-3 IGAMZCR.
03 - 07 May 2008
European Society of Endocrinology