The bovine pituitary contains follicle-stimulating hormone (FSH) and luteinizing hormone (LH), both of which can be used in superovulation. Successful superovulation can be evidenced by the presence of estrogen and progesterone receptors in the uterus. The aim of this study was to evaluate the potential of bovine pituitary extract (BPE) in inducing superovulation, based on the distribution and expression of estrogen receptor alpha (ERα) and progesterone receptor-A (PR-A) in rabbit uterine tissue. Six local female rabbits, weighing between 1.8–2.2 kg and having previously given birth, were used in this study. The rabbits were divided into two treatment groups (n=3): KL1, the control group, which was injected with physiological NaCl (2.6 ml total), and KL2, the treatment group, which was injected with BPE (2.6 ml total). Both groups received injections of physiological NaCl or BPE five times at 12-hour intervals. The injection volumes for each rabbit were as follows: 1 ml for the first injection, 0.5 ml for the second and third, and 0.3 ml for the fourth and fifth. Twelve hours after the final BPE injection, KL2 rabbits were administered 100 IU hCG and mated with male rabbits. KL1 rabbits were mated without hCG administration. On the 6th day after treatment, the rabbits were euthanized, and their uterine organs were collected, processed histologically, and stained using immunohistochemical staining with the avidin-biotin complex peroxidase (ABC) method. The distribution of ERα and PR-A in uterine tissue was analyzed descriptively. Differences in receptor expression between the two groups were assessed based on intensity scores, using the Mann-Whitney U test. The results showed the presence of both ERα and PR-A in the uterine glands, lamina epithelialis, and lamina muscularis of the rabbit endometrium. A significant difference in ERα expression was observed between KL1 and KL2 rabbits (P<0.05), while the difference in PR-A expression was highly significant (P<0.01). In conclusion, BPE treatment significantly increased the expression of ERα and PR-A in the endometrial layer of the rabbit uterus, suggesting that BPE can be used as an indicator of successful superovulation.
Keywords | Bovine pituitary extract, Erα, PR-A, Local rabbit, Superovulation, Uterus