A novel animal model to study hot flashes: no effect of gonadotropin-releasing hormone.
OBJECTIVE
Menopausal hot flashes compromise the quality of life for most women. The physiological mechanisms underlying hot flashes remain poorly understood, and the absence of an animal model to investigate hot flashes hinders investigations in this field.


METHODS
We first developed the sheep as a model to study peripheral skin temperature changes using fever-inducing lipopolysaccharide (LPS; 200 microg/kg) administered to ovary-intact ewes. Because a strong correlation between luteinizing hormone pulses and hot flashes has previously been reported, we then determined whether intravenous gonadotropin-releasing hormone (GnRH; 1 mg), a dose sufficient to elevate cerebrospinal fluid-GnRH concentrations, could modulate ear skin temperature in both ovariectomized and low-estrogen-replaced ovariectomized ewes.


RESULTS
Some ewes responded to LPS in heart rate and abdominal temperature, but there was no significant effect on either parameter or cheek temperature for the group. In contrast, LPS injection caused a significant (P < 0.001) change in skin temperature at the ear. Ear temperature showed no significant change in response to GnRH relative to control injections in both ovariectomized and low estrogen ewes.


CONCLUSIONS
We developed a model animal system in the ewe that can accurately detect small changes in peripheral skin temperature. This system has the potential to be extremely useful in future studies investigating the pathology of hot flashes and holds several advantages over previous model systems developed for this research. GnRH per se does not seem to be involved in thermoregulatory events.
Albertson
Asher J
AJ
Department of Zoology and Physiology and Neurobiology Program, University of Wyoming, Laramie, WY 82071, USA.
Skinner
Donal C
DC
D000704:Analysis of Variance; D000818:Animals; D001833:Body Temperature Regulation / Q000187:drug effects / Q000502:physiology; D015984:Causality; D002610:Cheek; D018592:Cross-Over Studies; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D004423:Ear; D005260:Female; D005334:Fever / Q000382:microbiology / Q000503:physiopathology; D007987:Gonadotropin-Releasing Hormone / Q000134:cerebrospinal fluid / Q000502:physiology* / Q000627:therapeutic use*; D006339:Heart Rate; D019584:Hot Flashes / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D007275:Injections, Intravenous; D008070:Lipopolysaccharides / Q000009:adverse effects; D007986:Luteinizing Hormone / Q000187:drug effects / Q000502:physiology; D008593:Menopause / Q000187:drug effects / Q000502:physiology; D010052:Ovariectomy; D012756:Sheep; D012881:Skin Temperature / Q000502:physiology
D008070:Lipopolysaccharides; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone