The relation of plasma lipids and pseudocholinesterase (PChE) activity was studied
in rats made hypothyroid by treatment with propylthiouracil (0.05% in drinking water
for 28 days) and in hypothyroid patients prior and after L-thyroxinetherapy (1. week
25-50 µg, 2.-4. week 100 µg daily). In rats, thyroid hormone deficiency caused a significant
increase in plasma and adipose tissue PChE activity as well as total plasma cholesterol
(TC) concentration, and a decrease in plasma triglyceride (TG) concentration. In contrast
to rats, thyroid-deficient humans demonstrated a decrease in plasma PChE activity
and an increase in both TC and TG, in comparison with euthyroid controls. After one
month's therapy with L-thyroxine, reversion of PChE activity and lipid concentrations
occurred. The opposite changes of PChE elicited by thyroid hormone deficiency in men
and rats are similar to the respective changes in lipoprotein lipase (LPL) activity,
observed by other authors. The inverse correlation between both PChE and LPL activity
and TG concentration suggests that PChE, similarly to LPL, may be involved in TG hydrolysis.
Key words
Pseudocholinesterase - Hypothyroidism - Cholesterol - Triglycerides
