EFFECTS OF UTERUS AND PROSTAGLANDIN-F2-ALPHA ON CORPORA-LUTEA IN MONGOLIAN GERBILS AND GUINEA-PIGS

  • 1 January 1976
    • journal article
    • research article
    • Vol. 37  (5) , 573-578
Abstract
One or both uterine horns were removed on postpartum day 6 (day 1 = parturition) in pseudopregnant gerbils. On day 16, the corpora lutea (CL) in unilaterally hysterectomized gerbils were smaller (P < 0.05) in the ovary adjacent to an intact horn than in the ovary adjacent to a removed horn. The CL were smaller in uterine-intact than in completely hysterectomized gerbils. In another experiment, the CL were smaller (P < 0.05) in pseudopregnant gerbils given a single intrauterine injection of a 30- or 20-.mu.g dose of prostaglandin F2.alpha. (PGF2.alpha.) on postpartum day 6 and then necropsied on day 10 than in gerbils given 10-, 5-, 1-, and 0-.mu.g doses; CL were smaller (P < 0.005) on the side ipsilateral to the treated horn than on the opposite side, although the interaction of dose and side was not significant. A single s.c. injection (0 or 30 .mu.g) of PGF2.alpha. was given to pseudopregnant gerbils on postpartum day 6. Litter size was adjusted to 0, 3, or 5 young on day 1. At necropsy on day 10, the CL were smaller in gerbils given the 30-.mu.g dose when all young were removed than when 3 or 5 young were present. In guinea pigs given a single i.m. injection of PGF2.alpha. at the dose level of 3,000 .mu.g/kg on day 7 and necropsied on day 10 of diestrus (day 1 = 1st day of vaginal closure), CL were significantly smaller than in guinea pigs which were given dose levels of 500 or 0 .mu.g/kg. A single injection of various doses (0, 100, 500, or 1,000 .mu.g/kg) of PGF2.alpha. was given into 1 uterine horn in guinea pigs on day 7. At necropsy, mean CL weight in each group was significantly different from each other; the response increased as the dose increased. Mean CL weight tended to be smaller (P < 0.1) on the side ipsilateral to the treated horn than on the opposite side, but the interaction of dose and side was not significant. Results indicated a uteroovarian relationship was involved in luteolysis in Mongolian gerbils and the relationship was predominantly on a local or unilateral basis operating between a uterine horn and the adjacent ovary. The efficacy of PGF2.alpha. administered through a local vs. a systemic route in both gerbils and guinea pigs implied that a predominantly local uteroovarian pathway for PGF2.alpha.-induced luteolysis existed in these species.