Diabetes, Vol 30, Issue 2 127-131, Copyright © 1981 by American Diabetes Association
Identification of human mononuclear leukocytes bearing receptors for somatostatin and glucagon
SJ Bhathena, J Louie, GP Schechter, RS Redman, L Wahl and L Recant
Mononuclear leukocytes (MNL) were isolated from human blood by
Ficoll-Hypaque. These cells were further separated into lymphocyte (L) and
monocyte (M) enriched fractions. L contained 99% lymphocytes and M
contained 74% monocytes, a threefold enrichment over MNL. Specific binding
to somatostatin, glucagon, and insulin was measured in the three fractions.
Binding of all three hormones in the M fraction was increased by a factor
of 3 compared with MNL and was linear with cell number. Binding of glucagon
and insulin to the L fraction was very low while, in contrast, somatostatin
binding was substantial and linear with lymphocyte number. Autoradiography
confirmed the binding of glucagon to monocytes and of somatostatin to both
monocytes and lymphocytes. Somatostatin is the first of the peptide
hormones shown to bind to both types of circulating mononuclear cells,
perhaps complicating quantification of somatostatin binding in disease
states in which differential alteration of binding of lymphocytes or
monocytes might occur.