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[A1CR]

The http://en.wikipedia.org/wiki/Ventromedial_hypothalamus
aspect of our
http://en.wikipedia.org/wiki/Hypothalamus appears to be
important in our CR
and possibly the tradeoff between our living longer and
healthier and our
sex lives. The level of glucose in the ventromedial
hypothalamus (VMH)
appears to be subject to our consumption or lack thereof, it
seems. The
first paper is free to all as an HTML and a pdf copy of the
full
text. Fasting (or CRing?) leads to lower levels of glucose
in the rat VML,
it seems. Repetition seems to result in lowered baseline
and fasting levels
of glucose in this region of our brains, and no change in
the response to
fasting, relatively.

The second paper below suggests that examining the
changes in glucose concentration over time shows an
exceptionally high level
for some time points, when comparing fasting with ad libitum
fed rats. Fig.
3 seems to show that there was only one approximately 300%
increase in the
VMH glucose concentration during the second and third
10-minute sample time
point after breaking the rat fasts. Their was a slight
nadir and then a
second rise in glucose until the last 10-minute sample time
point 120
minutes after feeding, it seems.

It was noted in the WUSTL studies that my glucose level
after fasting 11
hours and then rapidly drinking a sugar drink that my
glucose peaked in the
first 30 minute sampling time, which is earlier than normal.
Still, the
response was mild compared to what may be occurring in our
CRed brains,
especially after we break our fasts. My response was mild
also, which again
may discriminate what happens in our blood and brains. I
then had an
unexpected second rise in glucose, which may have been due
to my diminished
pancreas size due to CR that comes with never consuming such
a high levels
of rapidly released into the blood steam glucose in my CR
practice. Then
insulin responses may be temporarily insufficient to the
glucose loads. It
may make regard more seriously what occurs after we fast,
regarding how many
calories we consume and the glycemic index of those first
meals. Paul
McGlothin appears to make a science of his extended fasts
and erudite
selection of his break-fast routine.

de Vries MG, Arseneau LM, Lawson ME, Beverly JL.
Extracellular glucose in rat ventromedial hypothalamus
during acute and
recurrent hypoglycemia.
Diabetes. 2003 Nov;52(11):2767-73.
PMID: 14578295 http://tinyurl.com/gmeed http://tinyurl.com/jusw2

The activity of neurons in the ventromedial
hypothalamus (VMH)
important for initiating compensatory responses to
hypoglycemia is
influenced by ambient glucose concentration. In the present
study, we used
in vivo microdialysis to evaluate interstitial glucose
concentrations in rat
VMH under various glycemic conditions. Using the
zero-net-flux method,
steady-state glucose concentration in the VMH was
approximately 20% of blood
glucose (approximately 1.4 mmol/l) in fed rats but
approximately 14% of
blood glucose (approximately 0.7 mmol/l) in overnight-fasted
rats. During
moderate hypoglycemia VMH glucose declined in parallel with
blood glucose;
however, VMH glucose decreased to a greater degree than
blood glucose during
a more severe hypoglycemic episode, falling to 10 +/- 1.2%
of blood levels
(P < 0.01). To determine whether VMH glucose concentrations
were influenced
by recurrent episodes of hypoglycemia a second zero-net-flux
study was
conducted. Steady-state glucose concentrations in the VMH
were approximately
20% lower after three episodes of recurrent hypoglycemia, a
value 17.8 +/-
0.8% of blood glucose, although the relative change in VMH
glucose levels
during the first and fourth hypoglycemic episodes were
similar. From these
results, we conclude that interstitial glucose
concentrations in the VMH are
not maintained at a constant level and are more dynamic than
previously
proposed.

Mayer CH, Fink H, Rex A, Voigt JP.
Changes in extracellular hypothalamic glucose in relation to
feeding.
Eur J Neurosci. 2006 Sep;24(6):1695-1701.
PMID: 17004933

... rat ventromedial hypothalamus (VMH). Absolute
ambient glucose
concentrations in VMH were 1.43 mm in non-deprived rats as
compared to 0.94
mm after 24-h food deprivation. ... changes of glucose
concentration over
time were determined relative to a baseline. Experiments
were conducted in
relation to both, nutritional state (food-deprived rats vs.
non-deprived
rats) and feeding conditions throughout the experiment
(freely feeding rats
vs. rats without access to food). The results ... show
clearly that glucose
concentration in the VMH of rats increases significantly in
relation to food
intake. The data demonstrate that a 24-h food deprivation
before the
experiment further augments this increase (up to 350% from
baseline) as
compared to non-deprived conditions (up to 60% from
baseline). However, the
magnitude of food related increase in VMH glucose does not
correlate with
the individual amount of food eaten. In conclusion, the
present study shows
for the first time that VMH glucose concentrations increase
with food intake
in the early dark phase, indicating that such changes do not
only occur
after pharmacological treatment, but also under
physiological feeding
conditions. The results further indicate that the feeding
related increase
in VMH glucose depends on the nutritional state of the organism.