Effects of thyroid drugs on the larvae of the Brown trout, Salmo trutta

Abstract

Brown trout larvae, Salmo trutta L., were reared from hatching in solutions of the thyroid hormone, thyroxine, and the thyroid inhibitors, thiourea and thiouracil. Thyroxine treatment profoundly affected morphogenesis, while thiourea and thiouracil had little morphogenic effect. Thyroxine treatment caused abnormal growth of the head, and stimulated the rate of differentiation of the fins from the primitive fin fold, and the absorption of the external yolk sac. The epidermis and dermis were considerably thicker in thyroxine‐treated larvae than in control fish, and silvering of the skin was induced. Thiourea and thiouracil produced few morphogenic effects, but such effects as were evident were usually similar with both drugs, and opposite to those caused by thyroxine treatment.

Effects of hyperthyroidism in the development of the appendicular skeleton and muscles of zebrafish, with notes on evolutionary developmental pathology (Evo-Devo-Path)

“…it can enhance anabolic or catabolic metabolisms depending on the dosage 63 . Growth retardations have been reported to occur in different salmon species 54,64 and brown trouts 65 , but numerous authors reported acceleration of growth in various fish and reptiles, e.g. tilapia 66 , carp 67 , milkfish 63 , dwarf gouramy 68 and striped bass 69 , python 70 , and also cessation of molting in snakes 71 .…”

Effects of thyroxine administration on the growth and survival of pike silverside (Chirostoma estor) juveniles

“…In grouper and zebra ¢sh, THs accelerate pelvic ¢n growth and induce early di¡erentiation of pectoral ¢ns (reviewed in : Norris 1997;Bentley 1998;Power, Llewellyn, Faustino, Nowell, Bj˛rnsson, Einarsdottir, Canario & Sweeney 2001;Takei & Lorentz 2006;Blanton & Specker 2007). However,T 4 concentrations above 1 mM can impact survival negatively (Woodhead 1966;Nacario 1983;Lam 1985;Lam & Sharma 1985;De Jesus, Toledo & Simpas 1998;Eales 2006), but there is no information regarding the possible negative impact that T 4 exposure at lower concentrations (nM range) may exert on the thyroid function of treated ¢sh (Lam 1980;Lam & Sharma 1985;De Jesus et al 1998;Schreiber & Specker 1998).…”

A study of thyroid hormones in eggs and larvae of walleye, Stizostedion vitreum, and rainbow trout, Oncorhynchus mykiss

“…Because silvering is caused by guanine deposition, this suggests that thyroid hormone increased purine nucleotide metabolism (Dales and Hoar, 1954). Increased activity and loss of negative phototaxis are responses by some larval fish to thyroid hormone treatments; these behavioral responses could be important for survival if they enable the developing fish to navigate and find food (Woodhead, 1966;Lam, 1985).…”