Diabetes, Vol 30, Issue 1 70-76, Copyright © 1981 by American Diabetes Association
Insulin in insects and annelids
D LeRoith, MA Lesniak and J Roth
The fruitfly, Drosophila melanogaster, and the earthworm, Annelida
oligocheta, were extracted with acid-ethanol by a classic method for
recovering insulin from the pancreas. When each extract was filtered on a
Sephadex G-50 column, a distinct peak of insulin immunoreactivity. The
material in this peak had reactivity insulin (equivalent to 0.1 to 2 ng of
insulin/g wet weight) was recovered in the region typical of insulin
bioassay, measuring stimulation of glucose oxidation or lipogenesis by
isolated rat adipocytes. The bioactivity was partially or largely
neutralized by anti-insulin antibodies. In concordance with previous work
showing the presence of material very similar to insulin in the blowfly and
molluscs, we have confirmed the presence of insulin in insects and extended
the observation to the earthworms. These findings suggest that insulin is
more widespread in invertebrates than was previously thought. In a
companion study (Proc. Natl. Acad. Sci. USA 77:6184-88, 1980), we have
demonstrated material similar to insulin in unicellular organisms.