Separation of the “Colloid” from Living Thyroid Gland by Means of Centrifugal Force

Abstract

Following the lead of E. P. Lyon 1 and others, in some previous work I have shown that it is possible by means of a centrifugal force of about 3,000 times gravity to cause separation of heterogeneously dispersed materials inside living cells into distinct layers, depending on their density, without killing the cells, even though they were kept in the centrifuge for a week. In later centrifuge experiments 2 , 3 I separated crystals appearing homogeneous in the polarizing microscope and isolated them for chemical analysis. When these crystals were treated with alcohol they were decomposed into a phospholipin and a vitellin. Cavett, Rice and McClendon 4 reported that thyroglobulin treated with acetone and ether (as a substitute for alcohol, which denatured it) lost weight (increased in iodine percentage), which I interpreted as due to splitting off of some lipin. To test this hypothesis some method of getting thyroglobulin from thyroid without contamination with cell proteins was needed.

Thyroglobulin, the protein of the thyroid gland, is present in the sol or gel known as “colloid”, which is contained in the thyroid follicles. The follicles containing “colloid” are of a spheroidal shape formed by a single layer of flattened or cuboidal cells. Since spaces between these cells have been reported by cytologists it occurred to me that by the use of a sufficiently high centrifugal field, the “colloid” might be removed from the follicle.