Utilization of radioiodine by invertebrates, with special study of several annelida and mollusca

Abstract

EIGHT FIGURESTo most students of the thyroid gland of vertebrates it has seemed for a long time an oddity that diiodotyrosine, one of the precursors of thyroxine, was first identified in the scleroprotein skeleton of corals (Dreclisel, 1896). Even the most recent editions of the chemical handbooks (Hodgman, '52) still list diiodotyrosine as "iodogorgoic acid," the name given to it because it was found in the gorgonid coelenterates. Since the discovery of this substance further work has shown (Ackermann and Burchard, '41 ; Ackermann and Muller, '41 ; Closs, '31 ; Miirner, '07 ; Morner, '08 ; Roche, '52 ; Roche et al., '49 ; Roche et al., '51; Roche and Yagi, '52; JVheeler and Mendel, '21) that sponge and coral skeletons contain, in addition, monoiodotyrosine, mono-, and dibromotyrosine, and even small amounts of thyroxine itself. The recent careful work of Roche ( '52) has established these points, and compares also the characteristic varying proportions of halogenated and other amino acids in different taxonomic groupings of sponges and corallines.The knowledge that iodoproteins and thyrsxinz caa be found in such primitive members of the animal kingdom, and the fact tliat iodine is a common element in marine organisms of various phyletic groups (Cameron, ' l P l 5 ; Closs, '31), 'This study was aided by a contract between Columbia. University and the Office of Naval Research, Department of the Kavy.

Iodine Metabolism and Thyroid-Related Functions in Organisms Lacking Thyroid Follicles: Are Thyroid Hormones also Vitamins?

“…However, their notochord is not homologous to that of chordates, and they are no longer considered close chordate relatives. Early workers found autoradiographic evidence of radioiodide binding by surface epidermal and glandular tissues (105). Later radiochromatographic studies involving prolonged immersion in seawater containing radioiodide revealed MIT but no DIT or iodothyronines (106,107).…”

Investigations on the cuticle of the polychaete elytra using energy dispersive X-ray analysis

“…Br is found in the whole cuticle of the papilla, also between the few collagen fibers, whereas in the elytron-surface cuticle, Br is present only in the distal cuticle zone structure which possibly enables the agents to penetrate and adhere better between the fibers than in the matrix substance. Swan (1950) and Gorbman et al (1954) have shown in the case of several polychaetes that iodine 131 added to seawater is concentrated in the setae or cells of the bases of setae and the pharyngeal teeth, both composed of scleroproteins, in the form of monoiodotyrosine and diiodtyrosine. Siuda (1973) gives a survey of known organic structures containing halogen atoms, which are deemed " naturally occurring".…”

Evidence for the presence of thyroid stimulating hormone, thyroglobulin and their receptors in Eisenia fetida: a multilevel hormonal interface between the nervous system and the peripheral tissues

“…TGB has been found in the pharynx of an ascidian (Thorndyke 1978) and, although in small amounts, TSH. Some earlier studies incidentally discovered iodine utilization at the anterior part of the digestive system in annelids (Gorbman et al 1954), whereas immunohistochemical methods have shown TGB-like staining in the nervous system of Eisenia (Marcheggiano et al 1985). In addition to neurosecretory cell somata in the CG, the neurohaemal organ has been considered as a hormone storage region (Golding and Whittle 1977).…”

“…Many investigators have described type-A neurosecretory cells (Al-Yousuf 1988;Golding and Whittle 1977) as peptide-containing neurons and have established their role in reproduction. These cells are located in the superficial layer of the brain (dorsomedial and dorsolateral cells) and some of them secrete TGB (Gorbman et al 1954).…”