Biochemical Studies on the Thyrotropic Hormone

Abstract

With the use of paper chromatography, analytic studies on the character of sugar and the composition of amino acids contained in the thyrotropic hormone (TSH) and gonadotropin were made.
I. Composition of the sugars in TSH and Gonadotropin.
(a) Spectrophotometric analysis of Pretiron was made by hydrolizing two hours with NHCl 10cc. It was revealed that aldo-hexose and several other substances were present. Further serial electrophoretic examination showed that it was possible to obtain two fractions, one fraction possessed of active biologic substances and the other without such fraction.
The paperchromatographic examination of respective fraction showed that galactose and glucosamine were detectable in the biologically active portion and no galactose could be found in the non-biologically active fraction.
(b) The sugars in gonadotropin were similarly examined as tried in TSH. Galactose was also found in respective biologically active fraction. It has been proved that both TSH and gonadotropin contained galactose in the biologically active fractions but none could be found in non-active fraction when sugar content of the two hormones were compared.
II. Amino acids in TSH.
A TSH active fraction of the anterior pituitary was analized with high voltage electrophoretic method after 18-20 hour hydrolysis with 6 NHCl and fractionated into basic, acid and neutral amino acids. Further analysis of the fractionated amino acids was made by means of secondary paper chromatographic separaton. Eighteen different kinds of amino acids beginning with isoleucine and leucine have been isolated and quantitative analysis of respective composition of amino acid was made with DNP.
Comparative studies of amino acid formation and gonadotropin which closely resemble TSH as far as elements go, have revealed that the kinds of amino acids contained were identically the same though quantitatively different. From the above results, it is assumed that the galactose found in biologically active fraction of TSH and gonadotropin are common, and the amino acids found were no different though some quantitative variation had been observed. The author has assumed that the chemical nature of TSH and gonadotropin closely resemble in their glycoprotein characteristics.