This study aimed to investigate the efficiency of conjugating chitosan nanoparticles to letrozole (LET) on masculinization of rainbow trout larvae, Oncorhynchus mykiss. For this purpose, two treatments of LET, 1. 5 and 3 mg/kg food, and two treatments of letrozole-chitosan nanoparticles (LET-CS), 0. 5 and 1. 5 mg/kg were performed with a control group. Treatments began immediately after active larval swimming and continued for 60 days. The results showed that the amount of testosterone during the trial increased significantly (p<0. 05), so that the highest amount of testosterone was observed in 3 mg/kg LET and 1. 5 mg/kg LET-CS. However, estradiol was untraceable in all treatments. About 66. 6, 73. 33, 73. 33, 76. 66 and 43. 33% males were observed in 1. 5 mg/kg LET, 3 mg/kg LET, 0. 5 mg/kg LET-CS, 1. 5 mg/kg LET-CS and control, respectively. Despite the drug dosage in LET-CS treatments was half that of LET treatments, the sex ratio did not change among treatments (p≥ 0. 05), which showed a positive effect of CS in effectiveness of LET. In general, it can be stated that using CS for the administration of LET could be effective in inhibiting the production of estradiol, increasing the amount of testosterone, and thus changing the sex ratio of rainbow trout.

Combination therapy with clomiphene citrate plus gonadotropin (clomiphene citrate plus HMG) in induction ovulation reduces the gonadotropins dose but antiestrogenic effect of c.c. can decrease pregnancy rate. In a randomized clinical trial we compared 3 treatment protocol for induction ovulation and intra uterine insemination (I/o plus IUI) in women with infertility history more than one year, normal hysterosalpingogram (HSG), normal spermiogram and follicular stimulating hormone (FSH) < 10 IU/ml. 52 women were taken clomiphene citrate plus HMG, 52 women were received letrozole plus HMG and 28 women were taken HMG alone. Gonadotropin dose for induction ovulation in clomiphene citrate plus HMG group [mean 4.9 (1.5)] and letrozole plus HMG group significantly was lower than HMG group [mean 11 (4.5)](P < 0.05). Although size and number of mature follicule in 3 group were equal. In clomiphene citrate plus HMG group endometrial thickness was lower but level of estradiol obviously was higher than others (P < 0.05). Pregnancy rate in letrozole plus HMG group was 28%, in clomiphene citrate plus HMG group was 23% and in HMG group was 25%. In conclusion aromatase inhibitors like letrozole same as clomiphene can reduce gonadotropin dose in induction ovulation without anti estrogenic effect.

Introduction: The effect of letrozole, aromatase inhibitor on spermatogenesis has not been clarified. The study was to investigate the effect of letrozole, on serum hormone and semen parameters.Materials and Methods: The study included 50 infertile men with a low serum testosterone to estradiol ratio (<10) of the patients 30 were azoospermic and 20 were oligospermic. All men were treated with letrozole 2.5 mg/d for at least 3 months. Serum testosterone and estradiol levels, testosterone to estradiol ratios and total motile sperm count (TMSC) were compared before and after the treatment in all patients.Results: The range age was (25-42ys) and treatment duration was 3 months. Pre-treatment and post-treatment. Serum testosterone and estradiol levels, testosterone to estradiol ratios and TMCS are compared. In all patients, serum testosterone level significantly increased and serum estradiol level significantly decreased after the treatment. Testosterone to estradiol ratios and TMCS were significantly increasd in all patients. In patients with oligospermia, TMSC significantly increased from 3.12±1.2 milion to 12.4±2.5 milion after the treatment (p=0.005) in the azoospermic men, spermatozoa in the ejaculate, with a mean of 0.7±0.2 milion TMCS in 7 of 30 patients who were totally azoospermic before the treatment, although 23 patients remained still azoospermic after the treatment.Conclusion: letrozole as an aromatase inhibitor may be effectively used improve sperm parameters in infertile men with a low testosterone to estradiol ratio. In addition letrozole may have some improvements by providing sperm in the ejaculate infertile men with azoospermia.

Background: Infertility is characterized by the inability to obtain a successful pregnancy after 6 months or more with unprotected and regular intercourse. In developing countries, the incidence of infertility is 2%. The causes of infertility could be male factor or female factor, or mixed factor. Objective: This study was conducted with the aim of comparison the ovarian response to letrozole alone and letrozole plus dexamethasone in infertile women with poly cystic ovarian disease (PCOS). Materials and Methods: This randomized clinical trial was conducted on 120 infertile women with PCOS referred to Ali-Ebne-Abitaleb hospital, Zahedan, Iran from February to August 2017 into two groups: group I received letrozole alone and group II recived letrozole plus dexamethasone. The endometrial thickness, follicle diameter, and ovulation were evaluated and compared by ultrasound on days 12 to 14. Results: The mean thickness of endometrium was not different between two groups. Pregnancy rate was 8% in letrozole group and 23% in Letrozole plus Dexamethasone (p = 0. 024). Also, the mean diameter of follicles in two groups were not statistically significant. Conclusion: Overall, this study showed that dexamethasone may increase pregnancy rate.

Background: Recently, letrozole has been used to prevent moderate to severe ovarian hyperstimulation syndrome (OHSS) in assisted reproductive technology cycles due to its estrogen-reducing and androgen-increasing effects on the ovaries, affecting granulosa cells, and reducing vascular endothelial growth factor production. Objective: This study aimed to investigate the impact of letrozole consumption in preventing OHSS in infertile women with polycystic ovarian syndrome undergoing in vitro fertilization. Materials and Methods: In this cross-sectional study, among 1743 medical records of infertile women who were scheduled for oocyte retrieval at Research and Clinical Center for Infertility, Yazd, Iran. Data of 343 women with polycystic ovarian syndrome diagnosis and at risk of OHSS was extracted from March 2022-2023. The stimulation was carried out using a flexible gonadotropin releasing hormone antagonist protocol. Women were divided into 2 groups based on whether they received letrozole or not. In the letrozole group, 2.5 mg letrozole twice daily was continued from the trigger day, while in the control group, women did not receive letrozole. The parameters of OHSS severity, hospitalization rates, and the need for albumin prescription were analyzed. Results: 89 women in the letrozole and 254 women in the control group were examined. There was no statistically significant difference between groups in terms of age and body mass index; however, anti-Mullerian hormone was significantly higher than control group (7.53 ± 4.61 vs. 5.47 ± 3.63, p < 0.001). The parameters of OHSS severity, hospitalization rates, and the need for albumin prescription showed no significant differences between the groups. Conclusion: Recent study indicates that incorporating letrozole into the treatment of gonadotropinreleasing hormone antagonists and cabergoline does not reduce the OHSS severity.