Effect of acute physiological elevations of insulin on circulating androgen levels in nonobese women.
Level 4 - case-series / case-control
Non-randomized, uncontrolled before-and-after physiological clamp study
PubMed 1826009 · doi:10.1210/jcem-72-4-883
What was done
Nonobese women within 20% of ideal body weight underwent metabolic clamp studies after an overnight fast to assess the effects of physiological hyperinsulinemia on androgen levels. DHEAS, androstenedione, total testosterone, and free testosterone were measured before and after a euglycemic hyperinsulinemic clamp (exogenous insulin infused at 1 mU/kg·min) and a 2-hour hyperglycemic hyperinsulinemic clamp (endogenous insulin stimulated by raising plasma glucose 125 mg/dL above basal).
What was found
During the euglycemic clamp, plasma DHEAS declined from 6.2 ± 0.5 µmol/L to 5.2 ± 0.4 µmol/L (P < 0.001), while testosterone, free testosterone, and androstenedione showed no significant changes. During the hyperglycemic clamp, DHEAS fell from 6.7 ± 0.5 µmol/L to 5.1 ± 0.4 µmol/L (P < 0.001) without significant changes in the other androgens. The reduction in DHEAS did not correlate with the magnitude of insulin elevation, but directly correlated with baseline DHEAS levels in both euglycemic (r = 0.51, P < 0.05) and hyperglycemic (r = 0.75, P < 0.01) studies.
Why it matters
This indicates that physiological acute increases in insulin—whether from exogenous infusion or endogenous secretion—selectively reduce circulating DHEAS independently of other C-19 steroids, suggesting insulin alters DHEAS biosynthesis, secretion, or clearance.
Limits
The participant sample size is not stated in the abstract. The study examined only short-term (2-hour) acute changes in fasting, nonobese women, without a non-insulin time-control arm to evaluate potential diurnal variation in DHEAS levels.
Cited by
- contradicts When blood sugar rises, insulin rises, which directly leads to an increase in testosterone levels.