Glycogen content of rabbit tubular genitalia from mating through implantation.

Groups of five rabbits were killed at 0, 2, 4, 7, 10, 24, 48, 98, 168 and 240 hours after mating. The glycogen content of the lower half of the Fallopian tube was greater than in the upper half at each interval. Uterine and Fallopian tube levels of glycogen decreased during the interval from mating to ovulation. Both cervical and vaginal glycogen declined significantly within 24 hours after mating. Decidual uterine areas contained 1.5 and 5.0 times more glycogen on days 7 and 10, respectively, than interdecidual areas. Castrate rabbit Fallopian tube, uterus, cervix and vagina responded with glycogen synthesis to estradiol, but not to progesterone administration. The concentration of glycogen in the rabbit uterus is greatest in the circular muscle and in the walls of the vascular elements (Vaes and De Meyer, '57; Bo, '61). Glycogen concentration of the uterus increases during pregnancy, particularly in the mesometrial aspect of the myometrium where implantation occurs (Telfer and Hisaw, '57). Both myometrial and endometrial glycogen are elevated after administration of estrogen to immature (Zondek and Stein, '40) or mature castrate rabbits (Vaes and De Meyer, '57; Telfer and Hisaw, '57; Bo, '61) and rats (Brody and Westman, '58; Bitman, et al., '67). In contrast, progesterone administered alone (Brody and Westman, '58; Huber, '58), with estrogen (Zondek and Stein, '40; Vaes, '62; Telfer and Hisaw, '57) or with cortisone (Vaes, '62) depresses uterine glycogen. Among published evaluations of uterine glycogen synthesis, we have been unable to find changes in glycogen concentration of the tubular genitalia during various reproductive intervals. The purpose of the present investigation was to determine changes in glycogen content of rabbit tubular genitalia from mating through implantation. MATERIALS AND METHODS Rabbits of mixed breeding were mated with fertile bucks and five were killed at 0, 2, 4, 7, 10, 24, 48, 98, 168 and 240 hours later. An additional 15 animals were castrated and rested for seven days. Then either 2 mg progesterone, 5 pg of estradiol17p, or corn oil was injected subcutaneously, each into five rabbits daily for seven days. Among rabbits killed beyond seven hours after mating, only those with evidence of ovulation were used (ovulation points or corpora lutea). Tissues from the upper and lower Fallopian tube, uterus, cervix and vagina were removed and immediately frozen with dry ice. At the time of glycogen determination, tissue was weighed and hydrolyzed in 30% KOH, and glycogen was determined with anthrone reagent (Seifter, et al., '50). Results in micrograms of glycogen per 100 mg of wet tissue weight, were subjected to analysis of variance with orthogonal contrasts.