Menopausal Hot Flashes
This discussion of menopausal hot flashes is based on the presentation by Dr. Robert Freedman (Wayne State University).
Rhesus monkeys are excellent models to study the menopausal hot flash, because their reproductive and thermoregulatory systems are very similar to those of humans. Like humans, core body temperature (Tc) in rhesus monkeys is regulated between an upper threshold for sweating and a lower threshold for shivering. Within the intervening thermoneutral zone, fine adjustments in Tc are effected by vasomotor control. Sweating is the primary means of evaporative cooling in both species. The histology, histochemistry, relative distribution, mean weighted density, and percentage body surface area containing sweat glands are very similar in rhesus monkeys and in humans. canadian family pharmacy com
Hypothalamic heating in rhesus monkeys produced a significant linear relationship between hypothalamic temperature and sweating rate, as most probably occurs in humans. Thus, the anatomical and physiological similarities make the rhesus monkey an excellent analogue for the study of thermoregulatory phenomena such as hot flashes.
Two previous studies focused on hot flashes in monkeys. One used rhesus monkeys (three adult females aged 9 -14 yr) and was of relatively short duration (a few weeks) after ovariectomy with or without estrogen treatment. Spontaneous temperature fluctuations at the ear pinna were particularly prominent after ovariectomy, and estrogen-re-placement therapy tended to reduce these fluctuations. However, statistical significance was unclear. In the other, two female ovariectomized stumptail macaques showed forehead temperature fluctuations that were significantly reduced by estrogen.