[Analysis of iodine compounds in young rat skin in the period of suckling and in the adult. Effect of perchlorate].

In the suckling and adult rats equilibrated or no by 125I, cutaneous iodine analysed by dialysis and chromatography techniques (Dowex and Sephadex) was the purpose of this study. Dialysis studies had shown that most of steady or labelled skin iodine had an iodide form (90 to 95% of the total iodine). There were at least two intracellular iodide pools: the first one was quickly dialysable, in fact about 60 percent of initial radioactivity represented the intracellular iodide equilibrated with extracellular fluid. The other one wasn't or was little dialysable representing probably the cutaneous iodide storage compartment. Chromatography studies (Dowex or Sephadex) demonstrated that the skin of the young and adult rat contained T4 and T3 hormones in a small percentage. The iodide represented a value more than 90% of initial total radioactivity. Results concerning kinetic skin iodine, eight and twenty four hours after LT4(125)I injected to adults and to control and iodine deficient ten day old rats, confirmed those obtained here by Dowex chromatography and previous ones. Triiodothyronine (T3) might have an origin either in thyroid synthesis or in deiodination of T4. Consequently we may say that the skin of the 10 day and 14 day old rats presented a great accumulation of iodide. The perchlorate inhibited this storage. Indeed, in young deficient iodine rats at birth, cutaneous iodide concentrations were reduced whereas those of T4 and T3 as well as the ratio T3/T4 haven't been modified. Therefore the iodine deficiency seemed to have a few effects on the skin deiodinating activity. Indeed the skin of iodine deficient immature rat became unable to accumulate iodide. The main effect of the skin iodine deficiency was the inhibition of iodide transport from the extracellular fluid to the intracellular one, but not inside cellular structures.