Iodine binding in the endostyle of larval Branchiostoma lanceolatum (Cephalochordata).

Abstract:

:The asymmetrical endostyle of Branchiostoma larvae contains two different zones of mucus-producing cells which metamorphose to the paired zones 2 and 4 respectively in the endostyle of the adult. In both the larva and the adult these zones are parts of the food-trapping mechanism. An endostyle zone, which has a position corresponding to that of the paired iodinating zones in the endostyle of the adult, binds iodine selectively. The ultrastructure and labeling pattern indicate that the labeled cells in the larval endostyle belong to functionally different types. In one region of the iodinating zone iodine is mainly bound extracellularly at the apical cell surface. Also in the second region grains are located at the apical cell surface as well as over the cytoplasm and extracellularly at the basal plasma membrane. It is possible that iodination takes place in the lumen close to cells in the first region and that the labeled product is taken up and eventually released by cells of the second region. Our observations show that this primitive endostyle already has iodinating capacity and may synthesize and release thyroid hormones.

journal_name

Gen Comp Endocrinol

authors

Fredriksson G,Ericson LE,Olsson R

doi

10.1016/0016-6480(84)90028-5

subject

Has Abstract

pub_date

1984-11-01 00:00:00

pages

177-84

issue

2

eissn

0016-6480

issn

1095-6840

pii

0016-6480(84)90028-5

journal_volume

56

pub_type

杂志文章