Short-term effects of 3,5,3′-triiodothyronine on the intermediary metabolism of the dogfish sharkSqualus acanthias: Evidence from enzyme activities

The short‐term effects of 3,5,3′‐triiodothyronine (T3) on the intermediary metabolism of the liver of the Atlantic hagfish (Myxine glutinosa) were assessed by intraperitoneal injection of T3. Three hours postinjection, plasma T3 concentrations and the activities of key enzymes involved in glycolysis, lipid catabolism, and amino acid and oxidative metabolism were measured. Plasma T3 levels were significantly higher (P < 0.05) in T3‐treated fish when compared to control and pretreatment fish. T3‐treated fish had significantly higher (P < 0.05) activity of a pentose phosphate shunt enzyme, glucose‐6‐phosphate dehydrogenase, than control fish. The activity of an enzyme of lipid catabolism, carnitine palmitoyl transferase, increased significantly (P < 0.05) above that of the controls in fish treated with a low T3 dose. Other enzymes of amino acid metabolism and oxidative metabolism were not affected by T3 treatment. In the short‐term, T3 may modulate intermediary metabolism in the liver by increasing the catabolism of lipids to supply the energy requirements of biosynthetic processes. J. Exp. Zool. 278:333–337, 1997. © 1997 Wiley‐Liss, Inc.

show abstract

Short-term effects of 3,5,3′–triiodothyronine on the activity of selected enzymes of intermediary metabolism in the liver of the Atlantic hagfish,Myxine glutinosa

Leary

Reddy

Battersby

et al. 1997

J. Exp. Zool.

View full text Add to dashboard Cite

show abstract

Serum T4 and serum T3 concentrations in immature captive whitetip reef sharks,Triaenodon obesus

et al. 1999

View full text Add to dashboard Cite

Serum T3 (3,5,3′ triiodothyronine) and serum T4 (thyroxine) concentrations were repetitively assayed by radioimmunoassay over a three‐year period in two male and two female immature captive whitetip reef sharks, Triaenodon obesus. These sharks were maintained at the Waikiki Aquarium, Honolulu, Hawaii, in an open system holding pool receiving 568 liters per minute of water from a saltwater well with an iodide concentration of 0.076 mg/liter. No significant male‐female difference was observed for either serum T3 or serum T4. No seasonal pattern of serum T3 was detected (P = 0.07). Serum T3 concentrations ranged (mean ± SEM) from 0.52 to 0.83 ng/mL (0.67 ± 0.01; n = 64). A significant seasonal difference was observed for serum T4 (P < 0.001). Serum T4 concentration was higher in winter (October–January) with a mean (range ± SEM) of 6.58 ng/mL (1.48–8.77 ± 0.35; n = 24) and lower in summer (May–August) with a mean of 3.62 ng/mL (1.34–5.71 ± 0.22; n = 24). The thyroid hormone T4 has a seasonal rhythm even in immature sharks and may have an important role in physiology. J. Exp. Zool. 284:500–504, 1999. © 1999 Wiley‐Liss, Inc.

show abstract

Differential effects of thyroxine on metabolic enzymes and other macromolecules in a freshwater teleost

Tripathi

Verma

2003

J. Exp. Zool.

View full text Add to dashboard Cite

The effects of thyroxine (T(4)) on citrate synthase (CS), glucose 6-phosphate dehydrogenase (G6-PDH), lactate dehydrogenase (LDH), DNA, RNA, and protein of various tissues were studied to elucidate the hormonal control of metabolism in a freshwater catfish, Clarias batrachus. T(4) did not produce any significant effect on DNA content of the fish. The CS, RNA, and protein contents of brain, liver, and skeletal muscle of the fish exposed to thiourea for 28 days decreased approximately 50-58% as compared to their levels in control individuals. Injection of T(4) to thiourea-exposed fish produced about three-fold increases in CS, RNA, and protein. These macromolecular inductions by T(4) were blocked by actinomycin D or cycloheximide. This suggests T(4)-induced de novo synthesis of macromolecules and stimulation of aerobic capacity. However, the activities of G6-PDH and LDH of brain, liver, and skeletal muscle of the fish exposed to thiourea increased two times that of the activities in control individuals. Administration of T(4) to thiourea-exposed fish reduced LDH and G6-PDH activities by about 64-74%, which reflects T(4)-dependent inhibition in anaerobic power and selective anabolic activities of the HMP pathway. These differential effects of T(4) on some metabolic enzymes and other important macromolecules may be to meet the other T(4)-induced responses in the freshwater catfish.

show abstract

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

customersupport@researchsolutions.com

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Short-term effects of 3,5,3′-triiodothyronine on the intermediary metabolism of the dogfish sharkSqualus acanthias: Evidence from enzyme activities

Cited by 14 publications

References 27 publications

Short-term effects of 3,5,3′–triiodothyronine on the activity of selected enzymes of intermediary metabolism in the liver of the Atlantic hagfish,Myxine glutinosa

Short-term effects of 3,5,3′–triiodothyronine on the activity of selected enzymes of intermediary metabolism in the liver of the Atlantic hagfish,Myxine glutinosa

Serum T4 and serum T3 concentrations in immature captive whitetip reef sharks,Triaenodon obesus

Differential effects of thyroxine on metabolic enzymes and other macromolecules in a freshwater teleost

Contact Info

Product

Resources

About