title: [Biosynthesis of thyroglobulin in the endostyle of larva (ammocoetes) of a fresh water lamprey, Lampetra planeri B1].
abstract: The biosynthesis of thyroglobulin (Tg) in larva of a fresh-water lamprey, Lampetra planeri B1. has been established. This glycoprotein presents the same characters as in thyroid follicles of adult lampreys, as shown by its 18-19 S sedimentation coefficient and by the incorporation (in vivo and in vitro experiments of 4, 12, 72 h) of 125I, 3H-leucine and 3H-galactose. 3-8 S fractions and a 12 S monomer are the precursors of the 18-19 S protein. Total I % of Tg is very low (0.002 %) ; about 5 % of 125I are present in thyroid hormones (T3 and T4) in the 125I-labeled protein. The biosynthesis of 18-19 S Tg proceeds in larvs before the morphological differentiation of thyroid cells and follicles after metamorphosis. However, the biosynthesis of this protein is much slower in the endostyle of larvs, in which a primitive mechanism of storage is poorly efficient, compared to the accumulation of Tg in the colloid of the follicles of adults.
mesh_terms: D000818:Animals; D005399:Fishes / Q000378:metabolism*; D005690:Galactose / Q000378:metabolism; D006023:Glycoproteins / Q000096:biosynthesis; D007798:Lampreys / Q000378:metabolism*; D007814:Larva / Q000378:metabolism; D007930:Leucine / Q000378:metabolism; D013954:Thyroglobulin / Q000096:biosynthesis*; D013961:Thyroid Gland / Q000196:embryology
chemical_list: D006023:Glycoproteins; D013954:Thyroglobulin; D007930:Leucine; D005690:Galactose
vernacular_title: Sur la biosynthèse de thyroglobuline dans l'endostyle des larves (ammocoetes) d'une Lamproie d'eau douce, Lampetra planeri B1.