Altered expression of the two naturally occurring human insulin receptor variants in isolated adipocytes of non-insulin-dependent diabetes mellitus patients

The human insulin receptor gene is expressed in two variant isoforms which differ by the absence (HIR-A) or presence (HIR-B) of 12 amino acids in the COOH-terminus of the extracellular alpha-subunit as a consequence of alternative splicing of exon 11. Expression of the two variant isoforms is regulated in a tissue-specific manner. In this study, we have measured the levels of the two receptor variants in isolated adipocytes from 10 non-insulin-dependent diabetes mellitus (NIDDM) and 11 normal subjects using an immunological assay, based on the ability of a human anti-receptor autoantibody to discriminate between HIR-A and HIR-B. Results indicate that levels of HIR-B variant are increased in NIDDM patients.