Diabetes, Vol 40, Issue 6 693-700, Copyright © 1991 by American Diabetes Association
Opposing actions of dehydroepiandrosterone and testosterone on insulin sensitivity. In vivo and in vitro studies of hyperandrogenic females
CK Buffington, JR Givens and AE Kitabchi
Department of Medicine, University of Tennessee, Memphis 38163.
It has been hypothesized that the androgens testosterone and
dehydroepiandrosterone (DHEA) may have opposing actions on insulin
sensitivity. To test this hypothesis, we selected patients with polycystic
ovary syndrome (PCO) and hypertestosteronemia and a group of individuals
with adrenal hyperplasia (AH) and elevated DHEA and studied their 1)
insulin and glucose responses to a 75-g oral glucose tolerance test, 2)
insulin resistance by hypoglycemic responses to a standard dose of
intravenous (IV) insulin, and 3) insulin binding and pyruvate dehydrogenase
(PDH) responsiveness to insulin in phytohemagglutinin (PHA)-activated T
lymphocytes. PCO patients exhibited elevated basal and glucose-challenged
insulin levels and had blunted hypoglycemic responses to IV insulin.
Conversely, AH patients had hypoglycemic responses to IV insulin
significantly greater than and basal and glucose-challenged insulin levels
lower than the PCO patients and weight-matched control subjects. In vitro,
T-lymphocyte insulin binding of the PCO patients was 40-60% below control
values; in AH patients, insulin binding and PDH insulin sensitivity were
above those of the control subjects. Testosterone levels in all study
subjects were negatively correlated to T-lymphocyte insulin binding and
positively correlated to basal insulin, insulin area under the curve (AUC),
and insulin-glucose indices. DHEA levels were positively correlated to
insulin binding and inversely related to basal insulin, insulin AUC, and
insulin-glucose indices. In all instances, the parameters of insulin
sensitivity were more strongly correlated to individuals' ratios of DHEA to
testosterone than to either of these androgens alone.(ABSTRACT TRUNCATED AT
250 WORDS)