Recombinat hormones: Structure-function relationship of recombinant follicle stimulating hormone (Puregon(R))

After separation by means of preparative isoelectrofocusing,the isohormones of a Chinese hamster ovary (CHO)-derived recombinantfollicle stimulating hormone (rFSH, Puregon^®) were characterizedwith respect to structural and functional features. A carbohydrateanalysis revealed that rFSH isohormones with a low isoelectricpoint (pI) have a high sialic acid/galactose ratio and are richin tri- and tetra-antennary N-linked carbohydrate chains incomparison with the high pI isohormones. The relative basicisohormones exhibit receptor binding activity and intrinsicbioactivity 2–3-fold higher than the relative acidic isohormones.However, due to their lower clearance rate these acidic isohormonesdisplayed a 20-fold higher in-vivo bioactivity in the rat. Acomparison of the isohormone profile of rFSH and urinary FSH(Metrodin^®) revealed that rFSH contains about 2-fold morebasic isohormones with pl