Cytotoxic effects of nasal buserelin on nasal mucosal tissue in rabbits.

To investigate the cytotoxic effects of nasal buserelin on rabbit nasal mucosal tissue, twenty-four female rabbits were studied prospectively. The rabbits were divided into 4 groups including 6 rabbits. The rabbits' left noses were included in the all study groups: 150 µg/puff/day of buserelin acetate was administered topically twice daily during 21, 42 and 63 days. Saline was administered topically twice daily to the left nasal cavity in the control group. The nasal septal mucosal stripe tissue was carefully removed from underlaying cartilage after sedation. HE staining, Masson's trichrome, toluidine blue and TUNEL staining were used to evaluate mucosal changes. Each preparation was investigated via apoptotic cells, and they were accounted. Kruskal-Wallis test was used to evaluate nonparametric comparison of apoptotic cells. Mononuclear cells have been raised in the sub-epithelial connective tissue, nucleuses of epithelial cells in the apical region were pyknotic, and apoptotic cells were determined on 21-day group. In the 42-day group, nasal epithelial tissue was similar to 21-day group and epithelial cells including pyknotic nucleus were present in this group, too. In the 63-day group, epithelial cells were light colored. Venous sinuses in the sub-epithelial connective tissue were wide but not congested and not raised collagen filaments. In the intra-epithelial tissue, some of cells were TUNEL (+). Apoptotic cells were fewer in the control group according to 21-day group. In 42- and 63-day groups, these cells were fewer than in 21-day group. Numerical difference was present between the groups, but statistical significance was not found between the groups. We concluded that nasal buserelin cytotoxicity was not potent in the nasal cavity in rabbits. We use nasal buserelin in all indications with confidence.

Effects of tocotrienol from Bixa orellana (annatto) on bone histomorphometry in a male osteoporosis model induced by buserelin.

INTRODUCTION: Osteoporosis is a debilitating skeletal side effect of androgen deprivation therapy based on gonadotropin-releasing hormone (GnRH) agonist in men. Tocotrienol from Bixa orellana (annatto) has been demonstrated to offer protection against osteoporosis by exerting anabolic effects on bone. Thus, it may prevent osteoporosis among GnRH agonist users. OBJECTIVE: This study aimed to determine the effectiveness of annatto-tocotrienol on the bone turnover markers and bone histomorphometry in a model of male osteoporosis induced by buserelin (a GnRH agonist). METHODS: Forty-six three-months-old male Sprague-Dawley rats (three months old; 300-350 g) were randomly divided into six groups. The baseline control group (n = 6) was sacrificed at the onset of the study. The normal control group (n = 8) received corn oil (the vehicle of tocotrienol) orally daily and normal saline (the vehicle of buserelin) subcutaneously daily. The buserelin control (n = 8) received corn oil orally daily and subcutaneous buserelin injection 75 µg/kg/day daily. The calcium control (n = 8) received 1% calcium in drinking water and subcutaneous buserelin injection 75 µg/kg/day. The remaining rats were treated with two different treatments, i.e., (1) oral annatto tocotrienol at 60 mg/kg/day plus subcutaneous buserelin injection 75 µg/kg/day (n = 8); (2) oral annatto tocotrienol at 100 mg/kg/day plus subcutaneous buserelin injection 75 µg/kg/day (n = 8). The rats were injected with calcein twice before being sacrificed to label the bones. The rats were euthanized, and their blood and right femur were harvested at the end of the treatment for bone turnover markers and bone histomorphometry examination. RESULTS: Both serum osteocalcin and C-telopeptide of type 1 collagen were not significantly different between treated groups and buserelin control (P > 0.05). The buserelin control group had a significantly lower bone volume and higher eroded surface compared with the normal control group (P < 0.05). Both groups treated with annatto tocotrienol (60 mg/kg/day and 100 mg/kg/day) had significantly higher bone volume, trabecular thickness and osteoblast number, as well as a significantly lower single-labelled surface compared with the buserelin control (P < 0.05). Only rats treated with annatto tocotrienol 60 mg/kg/day had a significantly higher double-labelled surface compared with buserelin control (P < 0.05). CONCLUSION: Annatto tocotrienol can prevent trabecular bone loss by increasing the mineralising surface and osteoblasts number. Thus, it has a potential role in preventing bone loss in men using GnRH agonist.

Long­term follow­up of buserelin­induced enteric neuropathy in rats.

A few patients have been shown to develop severe abdominal pain and gastrointestinal dysmotility during treatment with gonadotropin­releasing hormone (GnRH) analogs. A rat model of enteric neuropathy has been developed by administration of the GnRH analog buserelin to rats. Loss of enteric neurons and ganglioneuritis throughout the gastrointestinal tract has been described, without other histopathological changes. The aim of the present study was to investigate the long­term effects of this rat model on body weight, and on morphology and inflammatory changes in the gastrointestinal tract. Rats were administered subcutaneous injections of buserelin or saline once daily for 5 days and allowed to recover for 3 weeks. This regimen was repeated four times. The rats were weighed weekly and were sacrificed 16 weeks after the fourth treatment. The bowel wall was measured by morphometry, and the presence of enteric neurons, mast cells, eosinophils and T­lymphocytes was evaluated. Buserelin­treated rats were shown to have a lower body weight at sacrifice, as compared with the controls (P<0.05). Compared with controls, buserelin treatment caused loss of myenteric neurons in the ileum and colon (P<0.01), a thinner circular muscle layer in ileum (P<0.05) and longitudinal muscle layer in colon (P<0.05), increased number of eosinophils in the submucosa of the ileum (P<0.05), and an increased number of T­lymphocytes in the submucosa and circular muscle layer of the fundus (P<0.01 and P<0.05, respectively) and circular muscle layer of the colon (P<0.05). Mast cells were equally distributed in the two groups. Thus, long­term follow­up of buserelin­induced enteric neuropathy reveals reduced body weight, loss of myenteric neurons, thinning of muscle layers, and increased numbers of eosinophils and T­lymphocytes in the gastrointestinal tract.

Experience with a potent LH-RH agonist, buserelin, alone and in combination with testosterone for antispermatogenic activity, reversibility and toxicity in langur monkey.

Chronic intermittent treatment of LH-RH superagonist Buserelin alone or in combination with testosterone enanthate were given to adult male langurs for 90 days to evaluate antispermatogenic activity of alone and combination therapy, maintenance of normal androgenicity, possible toxic effects of agonist treatment, related side effects of testosterone supplementation and complete reversibility of the procedure. A gradual decrease in sperm count was recorded in both treatment groups, along with reduced motility and vitality of the spermatozoa. In the combination group, oligospermia was achieved in 4 out of 5 animals, whereas, only 2 animals became oligospermic in the agonist alone group. Significant decrease in serum testosterone levels along with impaired libido and other testosterone withdrawal symptoms were observed in the Buserelin alone group, conversely normal testosterone levels and libido were observed in the combination group. An elevation in haematological variables and serum total protein concomitant with a slight gain in body weight of the animals were recorded in the combination group; these changes were not encountered in the agonist alone group. Reversibility of all the altered parameters to control range was observed in both treatment groups following 75 to 90 days of treatment withdrawal.

Induction of S-phase entry by a gonadotropin releasing hormone agonist (buserelin) in the frog, Rana esculenta, primary spermatogonia.

In the testis of the frog, Rana esculenta, mitotic activity of primary spermatogonia is regulated by gonadotropins and synergistically by testosterone. In addition GnRH-like material directly stimulates gonadal activity. Intact animals were treated with a GnRH agonist (GnRHa, buserelin, Hoechst) and/or a GnRH antagonist giving injections intraperitoneally on alternate days for 15 days. Moreover, testes were treated in vitro for 24 hr with GnRHa. 3H-thymidine and colchicine were used to assess the labelling and the mitotic index (LI and MI) of primary spermatogonia. Both LI and MI were increased by the treatment with GnRHa but the rate of cells measured by LI was significantly higher than that of cells measured by MI. Therefore, our results confirm the role of GnRH-like material as local regulator of the testicular activity in vertebrates and show its involvement in promoting the G1-S transition of spermatogonial cell cycle in the frog, Rana esculenta.

[Phase I study with LH-RH agonist, ICI 118630].

A single shot of 250 micrograms LH-RH agonist, ICI 118630 (Zoladex), was subcutaneously administered to four healthy male volunteers to investigate the safety and endocrinal effect of the drug. The safety of the drug was confirmed because no clinical problems in vital sign and general clinical tests were observed. The endocrinal reactions of LH, FSH and testosterone in blood were also observed proving that the drug was the LH-RH agonist.

Investigations of the carcinogenicity of the LH-RH analog buserelin (HOE 766) in rats using the subcutaneous route of administration.

A carcinogenicity study with the LH-RH analog buserelin (HOE 766) was conducted in male and female Wistar rats. The compound was administered subcutaneously daily for a period of 24 months to groups of 50 male and 50 female animals in doses of 0.0002, 0.0006, or 0.0018 mg/kg body wt, followed by a 6-month recovery period without any treatment. Male and female rats (100 each) received physiological saline and served as controls. The body weight development of all male rats was regular, but in females at all three dose levels significantly increased body weight gain in comparison to the control animals occurred. Food consumption was not affected in any group. No treatment-related changes in clinical signs and hematological parameters were noted. The chronic administration of HOE 766 did not influence the survival of the male rats while in females it was dose-dependently increased. Endocrinological examinations revealed decreased serum testosterone levels in males and reduced serum progesterone levels in females during the treatment period; the changes reverted to normal during the recovery period. Reduced weights of the testes and uteri as well as increased weights of the pituitaries and ovaries in females are compound-related. Histological examination of the animals which died intercurrently or were killed in extremis or at the end of the recovery period revealed irreversible and partly dose-dependent changes in testes and uterus, due to the pharmacodynamic properties of HOE 766, but gave no indication of any carcinogenic effect of the compound.