STOKES RADIUS OF HUMAN PITUITARY HORMONES AND DEMONSTRATION OF DISSOCIATION OF LUTEINIZING HORMONE

A technical modification, namely the use of radioiodine-labeled proteins, has been used in the gel filtration technique for the determination of the Stokes radius of human pituitary follicle-stimulating hormone, luteinizing hormone, somatotrophic hormone, and thyroid- stimulating hormone. Data are presented to justify the use of this technical modification. The Stokes radii of these pituitary hormones were found to be 32.2 Å for follicle-stimulating hormone, 22.2 Å for somatotrophic hormone, and 27.5 Å for thyroid-stimulating hormone. Two species of luteinizing hormone molecules were found, the larger having a Stokes radius of 30.2 Å and the smaller, 22.6 Å. The molecular weights of these species of luteinizing hormone were estimated to be 28,000 and 14,400. © 1969, American Chemical Society. All rights reserved.