Analogs of endoperoxide precursors of prostaglandins: failure to affect body temperature when injected into primary and secondary central temperature controls.

It is known that central administration of prostaglandins of the E series has marked effects on body temperature. The purpose in the present experiments was to learn whether stable analogs of the cyclic endoperoxide precursors of PGE2, PGF2alpha and PGD2, injected into the primary temperature control in the preoptic/anterior (PO/AH) hypothalamic region and into a presumed secondary control in the medulla oblongata, can produce rises in body temperature similar to those caused by PGE2. Injection of the analogs U-44069 and U-46619 (1.0 and 2.0 microng) into the PO/AH region of the rat, where both PGE2 and PGE1 caused hyperthermia, had no effect on Tre. Likewise, injections into the medulla oblongata, in the region where PGE2 and PGE1 caused hypothermia, were ineffective in altering body temperature. That neurons important to the control of body temperature are selectively sensitive to PGE2 and not to analogs of prostaglandin precursors suggests that local cyclic endoperoxides can influence body temperature only through bioconversion to prostaglandin.