title: Insulin-receptor activity in nondiabetic and diabetic urbanized South African black women.
abstract: OBJECTIVE
  To evaluate insulin receptor binding characteristics of urbanized South African black women with normal glucose tolerance and of patients with newly diagnosed untreated non-insulin-dependent diabetes mellitus (NIDDM).
  
  
  METHODS
  Four groups of 10 subjects each were selected by the following criteria: group A, young (20-39 yr) nonobese (body mass index [BMI] 19.0-24.9 kg/m2) nondiabetic women; group B, middle-aged (40-60 yr) nonobese nondiabetic women; group C, middle-aged obese (BMI greater than 30.0 kg/m2) nondiabetic women; and group D, middle-aged obese newly diagnosed but untreated female patients with NIDDM. Insulin binding to monocyte receptors was determined by radioreceptor assay. Fasting plasma samples were analyzed for glucose, insulin, C-peptide, and nonesterified fatty acids.
  
  
  RESULTS
  In the four groups studied, maximum specific binding and receptor concentration were highest in group A, with a progressive and significant decrease in values through groups B and C to group D. Significant inverse correlations were obtained between maximum specific binding, 50% inhibition dose, and total receptor concentration on the one hand and glucose, insulin, and NEFA on the other.
  
  
  CONCLUSIONS
  Our study of urban South African black women showed decreasing insulin-receptor activity with obesity and glucose intolerance. In patients with NIDDM, hyperglycemia and beta-cell dysfunction were associated with a reduction in receptor concentration. In this regard, our findings in South African blacks are consistent with results of similar studies of NIDDM in other communities.
authors.affiliation: Carbohydrate and Lipid Metabolism Research Group, University of the Witwatersrand Medical School, Johannesburg, South Africa.
authors.forename: V R
authors.initials: VR
authors.lastname: Panz
authors.forename: B I
authors.initials: BI
authors.lastname: Joffe
authors.forename: J R
authors.initials: JR
authors.lastname: Wing
authors.forename: F J
authors.initials: FJ
authors.lastname: Raal
authors.forename: H C
authors.initials: HC
authors.lastname: Seftel
mesh_terms: D000328:Adult; D000367:Age Factors; D044383:Black People; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000097:blood; D003920:Diabetes Mellitus / Q000097:blood*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism*; D009765:Obesity / Q000097:blood*; D011972:Receptor, Insulin / Q000378:metabolism*; D012016:Reference Values; D013019:South Africa; D014505:Urban Population
chemical_list: D001786:Blood Glucose; D002096:C-Peptide; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D011972:Receptor, Insulin