PROLONGED INTRAVENOUS INFUSION OF LABELLED IODOCOMPOUNDS IN THE RAT: [125I]IODIDE METABOLISM AND EFFECTS OF MODERATE DIETARY IODINE DEFICIENCY

in Journal of Endocrinology
Authors:
VIPA BOONNAMSIRI
Search for other papers by VIPA BOONNAMSIRI in
Current site
Google Scholar
PubMed
Close
,
J. C. KERMODE
Search for other papers by J. C. KERMODE in
Current site
Google Scholar
PubMed
Close
, and
B. D. THOMPSON
Search for other papers by B. D. THOMPSON in
Current site
Google Scholar
PubMed
Close
Restricted access
Rent on DeepDyve

Sign up for journal news

SUMMARY

Radio-iodide was administered by prolonged continuous intravenous infusion to rats maintained under iodine-replete conditions and in moderate iodine deficiency. A close approximation to equilibrium labelling was thereby achieved. Labelled iodocompounds extracted from various tissues were analysed by thin-layer chromatography.

Moderate iodine deficiency resulted in a slight increase in the ratio of mono-iodotyrosine to di-iodotyrosine in the thyroid. No change in the ratio of tri-iodothyronine (T3) to thyroxine (T4) was found in thyroid, plasma or skeletal muscle. Faecal excretion of T3 declined appreciably relative to that of T4.

Under iodine-replete conditions the ratio of thyroidal secretion rates of T3 and T4 was estimated to be more than three times higher than the ratio of these iodocompounds within the thyroid. Heterogeneity of thyroglobulin structure and function may explain these observations.

 

  • Collapse
  • Expand