Aims/hypothesis The insulin receptor (INSR) has two protein isoforms based on alternative splicing of exon 11. INSR-A promotes cell growth whereas INSR-B predominantly regulates glucose homeostasis. In this study we investigated whether weight loss regulates INSR alternative splicing and the expression of splicing factors in adipose tissue. Methods To determine the relative ratio of the INSR splice variants, we implemented the PCR-capillary electrophoresis method with adipose tissue samples from two weight-lossintervention studies, the Kuopio Obesity Surgery study (KOBS, n = 108) and a very low calorie diet (