Periovulatory increase in temperature difference within the rabbit oviduct.
BACKGROUND
Earlier studies demonstrated a small temperature difference between the sperm storage and fertilization sites within the oviducts of rabbits and pigs. Our aim was to reveal the time dependence of this temperature difference relative to ovulation, and to determine how this difference is generated-by temperature elevation at one of these sites or by temperature decrease at the other site.


METHODS
The temperature at the sperm storage site (at the isthmus near the uterotubal junction) and at the fertilization site (the isthmic-ampullary junction) of rabbit oviducts were measured before, during, and after ovulation by two probes, connected to digital thermometers. Rectal temperature was constantly measured and served as a control for body temperature.


RESULTS
The temperature difference between the fertilization site and the storage site was 0.8+/-0.2 degrees C before ovulation. This difference increased at ovulation, reaching 1.6+/-0.1 degrees C after ovulation (P<0.03). This increased difference was mainly due to temperature decrease in the sperm storage site.


CONCLUSIONS
The temperature-difference increase within the rabbit oviduct is generated at ovulation by a reduced temperature at the sperm storage site. This temperature gradient may play a role in mammalian reproduction via sperm thermotaxis.
Bahat
Anat
A
Department of Biological Chemistry, The Weizmann Institute of Science, 76100 Rehovot.
Eisenbach
Michael
M
Tur-Kaspa
Ilan
I
D000818:Animals; D001831:Body Temperature / Q000502:physiology*; D001833:Body Temperature Regulation / Q000502:physiology; D005260:Female; D005306:Fertilization / Q000502:physiology*; D008297:Male; D010057:Oviducts / Q000502:physiology*; D010060:Ovulation / Q000502:physiology*; D011817:Rabbits; D013094:Spermatozoa