Monkey CR-affected menstruation

[Guest guest]

Hi All,

An interesting model for how humans may be affected by CR has been presented and

described in a model system using our close cousins, the rhesus monkeys.

It may interest those of us who monitor our BMI that BMI was very similar in the

rhesus monkeys and they responded similarly to CR in this regard. However, also

revealed appears to be a great variability in the responses of the individual

monkeys to CR, in terms of BMI, hormones and menstruation parameters. Similar

variability may occur in human CRers?

The punch line of the full-text seemed to be that the system may be a model for

the

effects of CR on our bones. The response to CR of our bone health may interest

us

CRers with regard how variable may be our bone health and how their health may

variably be affected by our BMI and CR.

Definition of the rhesus monkey is:

rhesus: A monkey; the bhunder.

bhunder: An Indian monkey (Macacus Rhesus), protected by the Hindoos as sacred.

See

Rhesus.

The pdf is available and its unaltered presentation displayed tables in

partially

mirror image. It was difficult to partially compensate for this. The result of

the

compensation is inferior to the presentation in the original pdf, which was the

only

available full-text format that was available.

Lujan ME, Krzemien AA, Reid RL, Van Vugt DA.

Developing a model of nutritional amenorrhea in rhesus monkeys.

Endocrinology. 2005 Sep 29; [Epub ahead of print]

PMID: 16195399

Nutritional amenorrhea is defined as cessation of menstrual cycles resulting

from a

chronic negative energy balance. While it is agreed that nutritional amenorrhea

results from reduced secretion of gonadotropin releasing hormone (GnRH), the

neuroendocrine mechanisms leading to GnRH inhibition are poorly defined. Because

the

invasiveness of many neuroendocrine experimental approaches precludes its use in

the

clinical setting, we set out to establish a model of nutritional amenorrhea in

rhesus monkeys. Studies were conducted in four normal weight and one obese

female

rhesus monkey. Dietary intake was gradually reduced with the goal of achieving a

15

- 20% weight reduction. Dietary restriction inhibited ovulation in all animals.

The

weight loss required to inhibit ovulation ranged from 2 - 11% in the four normal

weight animals and was achieved with a 23% reduction in dietary intake. The time

of

initiating reduced food intake to first missed ovulation was 62 +/- 13 days.

Greater

weight loss (46% reduction) over a longer period (10 months) was required to

inhibit

ovulation in the obese monkey. The onset of anovulation was not preceded by

changes

in menstrual cycle length or progesterone secretion. Re-alimentation initiated

ovulation at a weight that approximated the animal's weight at the time of the

last

ovulatory cycle during dietary restriction. By contrast, caloric intake at the

return of ovulation during re-alimentation was 28% greater. This is the first

demonstration that chronic dietary restriction can inhibit ovulation in rhesus

monkeys. This model will be useful for studying the neuroendocrine mechanisms

involved in diet-induced anovulation in primates.

Al Pater, PhD; email: old542000@...

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