Adrenal steroid dysregulation in dystrophia myotonica

To evaluate circulating adrenal steroid hormones, cortisol diurnal rhythm and the negative feedback function of the cortisol axis in patients with dystrophia myotonica (DyM), a disease where metabolic disturbances, peripheral insulin insensitivity and cognitive dysfunction are common features.

Morning serum levels of dehydroepiandrosterone sulphate, androstenedione, 17 alpha-hydroxy progesterone and cortisol; morning serum levels of testosterone and insulin; diurnal rhythm of saliva cortisol; and an overnight dexamethasone suppression test, together with a cognitive screening test in men with DyM and in controls.

Outpatient clinic in co-operation with Umeå University Hospital.

Fifteen men with DyM and 13 age-matched controls.

Adrenal steroid hormone levels, diurnal rhythm of saliva cortisol, dexamethasone suppression test and Mini Mental State Examination scores.

Morning serum levels of dehydroepiandrosterone sulphate, androstenedione and 17 alpha-hydroxy progesterone were significantly decreased in DyM after inclusion of age and body mass index in multiple regression analyses (48, 26 and 32% decreases, respectively). An abnormal diurnal rhythm of saliva cortisol was present in all patients, mean saliva cortisol levels being significantly increased (33%) in DyM patients. Dexamethasone suppressibility did not differ between groups. DyM patients scored significantly lower on the Mini Mental State Examination (P < 0.001).

These results indicate an abnormal adrenal steroid hormone secretion in DyM, which may contribute to peripheral insulin sensitivity as well as cognitive impairment in these patients.