Decreased steroidogenic enzyme 17,20-lyase and increased 17-hydroxylase activities in type 2 diabetes mellitus.

Objective: To analyze activities of adrenal steroidogenic enzymes in type 2 diabetes mellitus, serum levels of 11 steroid hormones were measured simultaneously.

Subjects: We studied 130 patients with type 2 diabetes mellitus (74 men and 56 women between the ages of 40 and 69 years), whose blood glucose control had been poor (more than 10% in HbA(1c)). Age-matched normal subjects served as the control group.

Methods: Serum levels of steroid hormones (pregnenolone (Preg), progesterone (Prog), deoxycorticosterone (DOC), corticosterone (B), 17-hydroxypregnenolone (17-OH-Preg), 17-hydroxyprogesterone (17-OHP), 11-deoxycortisol (S), cortisol (F), dehydroepiandrosterone (DHEA) and Delta4-androstenedione (Delta4A)) were measured by HPLC/RIA methods. Fasting plasma glucose (FPG), HbA(1c), ACTH, serum immunoreactive insulin (IRI) and DHEA sulfate (DHEA-S) were also measured. We analyzed product/precursor ratios to assess relative activities of adrenal steroidogenic enzymes.

Results: Serum levels of ACTH and F were high and DHEA and DHEA-S were low in both male and female patients under poor blood glucose control. Following 6-months treatment with diet only or with sulfonylurea, FPG and HbA(1c) improved, and blood concentrations of ACTH and F decreased while DHEA and DHEA-S levels increased to within the normal range. DHEA/17-OH-Preg and Delta4A/17-OHP ratios, reflecting 17,20-lyase activity, were low before treatment and recovered to the normal range after treatment, and 17-OH-Preg/Preg and 17-OHP/Prog ratios, reflecting 17-hydroxylase activity, were high before treatment, and fell within the normal range after treatment. 3beta-Hydroxysteroid dehydrogenase, 21-hydroxylase and 11beta-hydroxylase activities remained within the normal range both before and after treatment.

Conclusions: These data suggest that the decrease in DHEA and DHEA-S concentrations together with the high F levels that occur in patients with type 2 diabetes mellitus is associated with low 17,20-lyase and high 17-hydroxylase activity in the adrenal steroidogenic enzymes. High insulin concentrations may further lower DHEA and DHEA-S levels.