The effect of experimental hyperthyroidism and hypothyroidism on 5'-monodeiodination of 3,3',5'-triiodothyronine and 3',5'-diiodothyronine by rat liver and kidney.

Abstract

To study the effect of alterations in thyroid status on 5'-monodeiodinase activity, conversions of rT3 to 3,3'-diiodothyronine and 3',5'-diiodothyronine (3',5'-T2) to 3'-monoiodothyronine were examined in vitro. Rats were injected either with T4 (10 micrograms/100 g BW, ip, daily for 12 days) to make them thyrotoxic or thyroidectomized to render them hypothyroid, and liver and kidney homogenates were prepared. Liver homogenates from hyperthyroid animals demonstrated a 2-fold increase in 5'-monodeiodination of both rT3 and 3',5'-T2; both reactions were also significantly increased in the kidneys of hyperthyroid rats. Hypothyroidism produced a significant decrease in 5'-deiodination of both rT3 and 3',5'-T2 in liver and kidney homogenates. These data indicate that the in vitro 5'-deiodination of both rT3 and 3',5'-T2 is increased in hyperthyroidism and decreased in hypothyroidism and suggest that these two iodothyronines are metabolized in a similar fashion in rat liver and kidney homogenates in states of altered thyroid function.

• Authors: R C Smallridge, L Wartofsky, K D Burman
• Journal: Endocrinology (Endocrinology) Vol. 111 Issue 6 Pg. 2066-9 (Dec 1982) ISSN: 0013-7227 [Print] United States
• PMID: 7140645 (Publication Type: Journal Article)

Chemical References

• Diiodothyronines
• Thyronines
• Triiodothyronine
• 3-monoiodothyronine
• Triiodothyronine, Reverse
• Iodine
• Thyroxine

Topics

• Animals
• Diiodothyronines (metabolism)
• Hyperthyroidism (chemically induced, metabolism)
• Hypothyroidism (metabolism)
• Iodine (metabolism)
• Kidney (metabolism)
• Liver (metabolism)
• Male
• Rats
• Thyroidectomy
• Thyronines (metabolism)
• Thyroxine
• Triiodothyronine (metabolism)
• Triiodothyronine, Reverse (metabolism)