DETECTION OF ANTI-PITUITARY AUTOANTIBODIES BY IMMUNOBLOTTING

A new approach to the detection of anti-pituitary autoantibodies by im munoblotting is presented. This method distinguishes pituitary membran e fraction from cytosolic fraction autoantigens and characterizes them by their molecular weight. A 45 kDa pituitary specific membrane prote in was identified as an autoantigen in one of 19 patients with idiopat hic growth hormone deficiency and the empty sella syndrome. A 43 kDa m embrane protein in pituitary and brain was identified as an autoantige n in one other patient with idiopathic growth hormone deficiency and i n one of 14 patients with secondary growth hormone deficiency. These a utoantibodies were not seen in any of 27 control subjects. Anti-pituit ary autoantibodies can be demonstrated by immunoblotting at titres of up to 1/1000. We conclude that immunoblotting is a useful method for t he detection of anti-pituitary autoantibodies.