Abstract
Thyroid dysfunction is accompanied by numerous changes in intermediary metabolism.
Retinol binding protein-4 (RBP-4) and adiponectin are 2 adipocytokines that have multiple
metabolic functions. The aim of our study was to examine serum RBP4 and adiponectin
levels in clinical (before and after therapy) and subclinical hyperthyroid and hypothyroid
subjects as compared to controls.
150 patients with thyroid dysfunction were recruited (65 hyperthyroid and 85 hypothyroid)
while 28 euthyroid subjects served as a control group. We measured anthropometric,
biochemical and hormonal (free T4, free T3, TSH, insulin) parameters in all participants.
RBP-4 and adiponectin were measured using commercial ELISA kits.
Mean baseline levels of RBP-4 were higher in patients with clinical hypothyroidism
(29.0±10.2 ng/ml, 25.1±12.6 ng/ml, 38.8±16.5 ng/ml, 31.9±13.2 ng/ml, 20.4±8.2 ng/ml
in patients with hyperthyroidism, subclinical hyperthryrodism, hypothyroidism, subclinical
hypothyroidism and controls respectively, F=4.86, P<0.001) and decreased significantly in patients with clinical hyperthyroidism and
hypothyroidism after normalization of thyroid hormones’ levels (from 29.0±10.2 to
24.9±8.4 ng/ml, p=0.003 and from 38.8±16.5 to 29.0±10.8 ng/ml, p=0.001 respectively).
We did not observe analogous changes in adiponectin levels in any of the studied groups.
RBP-4 levels are higher in patients with clinical hypothyroidism and exhibit a marked
decrease after normalization of thyroid function in both hyper and hypothyroid patients.
We suggest that RBP-4 may play a role in the metabolic disturbances which accompany
thyroid dysfunction.
Key words
retinol binding protein-4 (RBP-4) - adiponectin - hyperthyroidism - hypothyroidism
- insulin resistance