Summary
In order to clarify a possible relationship between opioid peptides and glucose homeostasis
in obesity we studied Beta-Endorphin (B-Ep), ACTH, cortisol and insulin plasma levels
in response to an oral glucose tolerance test (OGTT) in 8 subjects after a hypocaloric
diet for 90 days. We obtained through this treatment a weight loss superior to 30%
of the initial weight excess (WE) compared with ideal body weight. Moreover, we compared
the obtained results with our preliminary study that was performed with the same protocol
but without caloric restriction.
B-Ep was measured by RIA after silicic acid extraction and G75 Sephadex column chromatography.
ACTH, insulin and cortisol were measured directly on plasma by an RIA method. Basal
and during OGTT-induced levels of glucose, insulin, ACTH and cortisol decreased in
comparison with the values obtained before diet. Conversely, B-Ep remained higher
than normal both in the basal condition and during OGTT, and showed values consistently
similar to those before diet. These data show that hyperinsulinemia is corrected by
weight loss, while hyperbetaendorphinemia remains unchanged. Accordingly, it can be
suggested that no direct relationship occurs between hyper-B-Ep-hyper-IRI in obesity.
A further insight into the role of hyper-B-Ep in obesity is, thus, necessary, assuming
as hypothesis that the increase in B-Ep may be a cause and not a corollary of the
polymorphic aspects of obesity.
Key words
ACTH - Beta-Endorphin - Cortisol - OGTT - Obesity - Hypocaloric Diet
