Cell-free translation of the rat pituitary messenger RNA coding for the precursors of α and β subunits of lutropin

Abstract

Lutropin is a glycoprotein belonging to a group of pituitary glycoprotein hormones which includes also follitropin and thyrotropin. It is composed of two dissimilar, noncovalently linked subunits, (Y and /3. The amino acid sequences of (Y and fl subunits of glycoprotein hormones from many species have been established and are well known. Within a species, the sequence is identical or nearly identical for (Y subunits of all pituitary hormones. In the human being, it is also identical to that of a placental glycoprotein hormone, chorionic gonadotropin. The amino acid sequence of the hormone-specific fl subunits differs, although considerable homology exists in some portions of their primary structure (reviewed in [ 1 I). Each subunit of LH and hCG contains two N-asparaginelinked oligosaccharides. Astructure has been proposed for asparagine-linked oligosaccharides of human LH and CC; these might be identical [2.3]. Messenger RNA has been extracted from placental tissue and has been translated in vitro by systems derived from wheat-germ embryo, ascites tumors or reticulocyte lysates [4-71. The first evidence for the cell-free synthesis of LHa and LHp from bovine origin by separate mRNAs appeared in [8,9].