Insulin receptor studies of erythrocytes and mononuclear leucocytes in phasic insulin diabetes mellitus.

This study was designed to investigate any diferences in cellular binding of insulin between phasic insulin-dependent (malnutrition-related) diabetes mellitus (PIDDM) and insulin-dependent, non-insulin-dependent, and normal controls. Isolated, washed red and white blood cells obtained after 12 - 14hr fast, were separately incubated with varying concentrations of non-radioactive insulin, and a fixed quantity of radioactively labellede insulin. After the 3hr incubation, cells were washed with buffer, and radioactivity determined on an autogamma counter. Percentage binding, receptor sites number and affinity were all determined by linear regression of the Scathard plot. Fasting plasma insulin and glucose levels were were also assayed. The results obtained showed decreased binding of insulin in red blood cells (11.3+or -1.3%) and white blood cells 2.9 + or -o.5%) in PIDDM. This was due to decreased receptor sites (red blood cells 39+ or -11; white blood cells 0.5+ or -0.11x 10 to the 4th) as well as decreased affinity (red blood cells 0.14+ or -0.03 x 10 to the 9th M-1; white blood cells 0.17 + or -0.04 x10 to the 9th M-1) when compared to the normal and diabetic (both insulin and non-insulin-dependent) controls. Phasic insulin-dependent diabetes (malnutition-related diabetes mellitus) is characterized by decreased red and white cellular binding to insiulin, in addition to decreased production of insulin (AU)