Although the @entity2777 ( @entity2777 ) of the approximately 150-kDa insulin-like growth factor (IGF)-binding protein (IGFBP) complex was described over a decade ago, details of @entity2777 physiology have remained largely uncertain. We evaluated antibodies to synthetic @entity1 @entity2777 and constructed a noncompetitive @entity2777 enzyme-linked immunosorbent assay. Whereas uncomplexed @entity2777 is directly measured, determination of total levels required sample pretreatment with @entity214 , which was found to optimally dissociate complexed @entity2777 and significantly enhance @entity2777 immunoreactivity. @entity2777 in random adult sera was approximately 50% uncomplexed, and samples devoid of complexed @entity2777 by immunoaffinity separation contained about 54% of the total levels. Serum @entity2777 fractionated by gel filtration high performance liquid chromatography eluted in a single peak at approximately 150 kDa with @entity442 and @entity2301 , but appeared at about 400-500 kDa after sample acidification and fractionation under acidic condition. The unexpected shift in @entity2777 immunoreactivity remained unchanged when acid-neutralized or @entity214 -treated samples were fractionated under neutral pH and was reproducible when the 150-kDa complex was isolated, treated with acid or @entity214 , and rechromatographed. @entity2777 in adult sera more tightly correlated with @entity2301 than @entity442 or @entity5100 . The total levels (mean +/- SD) were 16.7 +/- 3.7 mg/L in 22 normal subjects, 28.3 +/- 8.1 mg/L in 20 acromegalic @entity1 , and 9.5 +/- 3.8 in 32 @entity2338 adults. Little or no @entity2777 was detectable in amniotic fluid, cerebrospinal fluid, seminal plasma, or milk, whereas high levels were present in synovial fluid. The development of @entity2777 enzyme-linked immunosorbent assay should greatly facilitate further investigations of this unique glycoprotein.

Acid-labile subunit of XXXX insulin-like growth factor-binding protein complex: measurement, molecular, and clinical evaluation.

@entity1 :: ('9606', 'Species') :: ['human', 'patients'] @entity2338 :: ('MESH:D004393', 'Disease') :: ['GH-deficient'] @entity2301 :: ('3486', 'Gene') :: ['IGFBP-3'] @entity442 :: ('3479', 'Gene') :: ['IGF-I'] @entity5100 :: ('3481', 'Gene') :: ['IGF-II'] @entity2777 :: ('MESH:D005166', 'Disease') :: ['ALS', 'acid-labile subunit'] @entity214 :: ('CHEBI:8984', 'Chemical') :: ['SDS']
@entity1 :: (9606,Species) :: ['human']
