Pituitary function in patients with autoimmune type 1 diabetes evaluated by CRH test
K Simunkova1,2, M Duskova2, L Starka2, M Hill2, J Kubatova2 & K Vondra2
This work aimed at acquiring data on pituitary response to CRH test in autoimmune type 1 diabetics with adult onset with/without thyroid autoimmunity. Our previous study showed 25% of such diabetic patients without clinical and immunological signs of adrenal insufficiency had lower response to the Synacthen test with normal basal levels of ACTH and cortisol.
Twenty-seven diabetics were investigated; 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/m2, HbA1c 7.2±1.2%. The group of patients consisted of 13 diabetics without and 14 diabetics with thyroid autoimmunity. The study was approved by the ethical committee.
The pituitary function was tested by CRH test. We evaluated serum ACTH and cortisol, salivary cortisol, thyroid function and metabolic paramerts of diabetics.
The group of patients with subnormal cortisol response to Synacthen showed a significantly lower cortisol response but a significantly higher ACTH response to CRH test. We divided this group to diabetics with and without thyroid autoimmunity. We found significantly lower cortisol response to CRH in diabetics without thyroid autoimmunity but significantly higher ACTH response to CRH, in comparison with diabetics with thyroid autoimmunity.
The results indicate that both groups of patients with subnormal response to Synacthen required the higher levels of ACTH to achieve normal cortisol response to CRH in contrast to group of patients with normal cortisol response to Synacthen. This higher activity on the pituitary level may be the first step of latent adrenocortical hypofunction to offset the stressful event. These results obtained may contribute to better understanding latent adrenal insuficiency adaptation in type 1 diabetics. The study was supported by grant no. NT 11 277 and NT 12340-5 of the IGA MZCR.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This work was supported, however funding details unavailable.