Re: [Paddlewise] cold hand adaption

> Philip Torrens wrote:
>
> > [snip] I thought I'd read somewhere that studies with
> > Arctic fishermen had suggested there was actually a process of
> > neovascularization (spelling?), that is the individuals actually grew
> > additional blood vessels in their hands which allowed them to shunt
greater
> > quantities of warm blood into the extremities.
>
> Maybe, but not needed to explain the effect.  See below.
>
> > Sounds plausible to this layman - our muscles, red blood cell count,
resting
> > heart rate and so on certainly respond to exercise, exposure to
altitude,
> > etc. On the other hand, I suppose it could be a desperate rear-guard
action
> > by the last of the LaMarckist evolutionists, surrounded by Darwinists.
> > Any doctors or scientists on the list care to comment on the possibility
of
> > this "change in the phenotype?
>
> ...

I know virtually nothing about the topic, but there is a behavior that some
organisms (e coli, rats, some plants, humans) exhibit that is called "heat
shock response" that might be at play, at the molecular level.  As I
understand it (which may be off), when exposed to temparatures significantly
over or under what the organisms are used to, heat shock response factors
(proteins of some sort) activate the synthesis of heat shock proteins
(hsp's) through RNA-transcription.  These heat shock proteins serve to
regulate and repair damage to cells at the more extreme temperatures.

Apparently, hsp generation can continue for several days after the initial
heat shock.  I imagine that continued heat shock would result in a
continuous generation of the heat shock proteins required to allow the
organism to survive in the more extreme temperatures.  The behavior is
consistent with the observation that after the heat shock is removed the
tolerance dissipates.

BTW, I got this info from a friend who minored in molecular biology in
college.  Any current biological experts care to comment on this theory?

Evan

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