Specimens of serum from ١٦٨ healthy subjects (٨٠ men and ٨٨ women, ages
١٨ to ٧٨ years)were divided into three groups: fresh, storage at ٤°C, and
freezing at-٢٠°C .
Periodic essays for the activity of Butrylcholinesterase (BChE,EC. ٣٫١٫١٫٨)
were
made on each frozen and unfrozen specimen. Serum frozen at-٢٠°C and
left at ٤°C gave results similar to those from fresh specimens. Comparison of
samples from men and women revealed significantly higher activity in men
than in women (P<٠٫٠٠١). Activity was greatest in men aged ١٨-٥٠ years and
then declined to slightly lower values. In women the activity was less in those
under ٥٠ years old than in those above ٥٠.
