Identification of insulin-like growth factor-binding protein-2 (IGF-BP-2) and a low molecular weight IGF-BP in human seminal plasma.

Three distinct binding proteins for the insulin-like growth factors (IGF-BPs) have recently had their cDNAs cloned and sequenced. We have evaluated IGF-BP expression in normal, oligospermic and azospermic human seminal plasma (SP), and have identified IGF-BP-2 in all samples. Additionally, SP contains a non-glycosylated low molecular weight IGF-BP (24K), which does not appear to be structurally or immunologically related to IGF-BP-1, -2 or -3.