Evidence of the Presence of Thyroid Hormones in Achatina fulica Snails

Abstract

The objective of this study was to identify thyroid hormones and to examine their putative site of synthesis in Achatina fulica snails. For this purpose, radioimmunoassays were performed for T 3 and T 4 before and after long starvation with or without hemolymph deproteinization. Sodium/iodide symporter activity in vivo was analyzed through 125 I administration with and without KClO 4 pretreatment. Only T 4 was detected, and its concentration decreased due to starvation or deproteinization. However, high-performance liquid chromatography analysis also showed the presence of T 2 and T 3 apart from T 4 , but rT 3 was not detected in the A. fulica hemolymph. The sodium/iodide symporter activity was greater in cerebral ganglia than digestive gland, but KClO 4 treatment did not inhibit iodide uptake in any of the tissues analyzed. Altogether, our data confirm for the first time the presence of thyroid hormones in A. fulica snails and suggest their participation in the metabolism control in this species, although the putative site of hormone biosynthesis remains to be elucidated.

Thyroid Hormones in Hemolymph of Red King Crabs from the Barents Sea

“…They concluded that these oysters have the ability to synthesize thyroid hormones endogenously. Later radioimmunoassay analyses have shown the presence of T4 (concentration 3.49 ± 0.55 µg dL -1 ) in hemolymph of the giant African snail Achatina fulica [13]. The authors also found that the thyroxine level decreased significantly to 2.27 ± 0.16 µg dL -1 as a result of 4-week starvation.…”

“…Heyland et al [10] suggested the presence of endogenous thyroid hormone signaling in echinoderms and mollusks, which may reflect the existence of iodination processes. There are only a few reports concerning thyroid hormone profiles in invertebrates, including terrestrial gastropods, marine bivalves, and mud crabs [11][12][13]. Because thyroid hormones are able to affect reproduction processes in invertebrates, these substances are considered promising agents in shellfish aquaculture [14][15][16].…”

Thyroid‐like hormone signaling in invertebrates and its potential role in initial screening of thyroid hormone system disrupting chemicals

“…Thyroid hormone‐like substances have also been detected in the mollusks C. gigas and Achatina fulica (Huang, Xu, Qu, Zhang, et al, 2015; Lustrino et al, 2017 ). Both T3 and T4 were detected during embryogenesis and larval development of C. gigas using HPLC and LC/MS (Huang, Xu, Qu, Zhang, et al, 2015).…”

Hemolymph of molluscan origin: from biochemistry to modern biomaterials science

“…The main function of this fluid, which exists in an open circulatory system, is the transport of oxygen, metabolites, and other components essential for the life of mollusks. It is composed mainly of water, but also of inorganic salts and organic compounds, mostly carbohydrates, proteins, lipids, enzymes, respiratory agents (hemocyanin), and free suspended cells called hemocytes [17,30,[68][69][70][71][72][73][74][75][76][77] (see Fig. 1).…”