SEASONAL VARIATION IN SERUM T3 AND T4 LEVELS IN MAN.

Abstract

In a group of 13 healthy male adults in the Netherlands, a seasonal variation in circulating serum thyroxine (T4) and triiodothyronine (T3) levels was found, inversely correlating with the seasonally altering environmental temperature. Lowest serum T4 and T3 levels were found in the summer.