Search Results

You are looking at 1 - 3 of 3 items for

  • Author: Khalid Ataya x
Clear All Modify Search
Restricted access

Khalid Ataya, Magdy Tadros and Alfida Ramahi

Abstract.

To study the effect of long-term use of GnRH agonists on the number and size distribution of ovarian follicles, two experiments were performed on adult female rats. Treatment was continued for 52 days in Experiment 1 and for 229 days in Experiment 2. Every sixteenth section from one ovary of each rat was examined using a light microscope attached to a BioQuant image analysis computer system. In Experiment 3, control and previously treated rats were mated with known male breeders and the number and normalcy of the offspring evaluated. The results indicate that in rats treated with GnRH agonist: 1) the total number of follicles, the number and percentage of follicles less than 35 μm in diameter were significantly higher than in the control group; 2) the number and percentage of follicles greater than 50 μm in diameter were significantly lower than control; and 3) the number of rats that got pregnant and the litter size were not significantly different from control. We conclude that GnRH agonists inhibit the physiologic process of follicle recruitment and loss and that fertility is preserved after long-treatment administration of GnRH agonists.

Restricted access

Khalid M. Ataya, Wael Sakr, Charla M. Blacker, Milton G. Mutchnick and Zuhair A. Latif

Abstract.

The potential clinical applications of GnRH agonists are growing. We studied the effects of two GnRH agonists on the adult female rat thymus in 4 experiments. GnRH agonists administered sc and continuously significantly increased wet and dry thymic weights (absolute and relative). Thymic enlargement was related to the duration of treatment with GnRH agonists. The maximum increase in thymic weight occurred at approximately 18 days following initiation of treatment with GnRH agonists. Thymic enlargement does not appear to involve enhanced mitotic activity as measured by incorporation of tritiated thymidine into thymic tissue and thymic DNA. Histologic examination and computer-assisted morphometric analysis of thymuses indicated an increase in cortex to medulla ratio most pronounced at 10 and 18 days of GnRH agonist treatment. No consistent increases in splenic weight or bone marrow cell counts were observed. Thymosin alpha-1 but not thymosin beta-4 increased in GnRH agonist-treated rats. Thymic weight correlated negatively with ovarian and uterine weights, relative adrenal weight, serum estradiol, LH, and positively with thymosin alpha-1. Exogenous estrogen administration reversed GnRH agonist-induced thymic weight increase. Whether GnRH agonists have direct thymic effects remains to be determined.

Restricted access

Charla M. Blacker, Khalid M. Ataya, Ruth T. Savoy-Moore, Marappa G. Subramanian, Milton G. Mutchnick and Joseph C. Dunbar

Abstract.

To evaluate the effects of a gonadotropin-releasing hormone agonist on non-reproductive systems, we administered [D-Leu 6, Des-gly 10]-GnRH ethylamide (leuprolide; 5 μg/day) for 21 days to female Sprague-Dawley rats. In Experiment 1, continuous infusion (Alzet minipumps sc) was compared to injection. Increased thymus and body weights and decreased estradiol and uterine weights were noted for both administration methods. Spleen weight increased only in rats treated by continuous infusion. Ovary, kidney and liver weights did not change. Only leuprolide-injected rats had elevated LH with decreased corticosterone and ACTH levels, possibly related to the injection process. Glucose, insulin, progesterone, FSH and corticosterone/ACTH were not different. In Experiment 2, intact and ovariectomized rats were implanted with minipumps delivering leuprolide or 0.9% NaCl. Body and thymus weights increased, whereas uterine weight and estradiol declined in both leuprolide-treated and ovariectomized rats. No synergism between leuprolide and ovariectomy was noted. Thymosin α1, but not thymosin β4, increased in leuprolide-treated ovariectomized rats. Peripheral white blood cell count was elevated in leuprolide-treated intact rats and ovariectomized rats. In bone marrow, non-nucleated cell count declined in leuprolide-treated intact rats, contributing to the decreased total cell count in this group. Nucleated cell count was unaffected. Therefore, thymus weight gain was accompanied only in some cases by functional changes. Our results demonstrate that leuprolide affects non-reproductive systems, in a similar manner to ovariectomy. We suggest that such alterations may be due to the hypoestrogenic environment produced by leuprolide.