Effect of letrozole in hypothalamus and gonads of spixs yellow-toothed cavy during sexual development

Author(s)

Maria Angélica Machado Arroyo

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2017-09-11

Examining board members

Antônio Chaves de Assís Neto; José Roberto Kfoury Junior; Moacir Franco de Oliveira; Flávia Thomaz Veréchia Pereira; Ricardo José Garcia Pereira

• Advisor: Antônio Chaves de Assís Neto

Abstract

Letrozole is used as a therapeutic in reproductive disorders caused by high estrogen levels. The enzyme cytochrome P450 aromatase biosynthesizes estrogens from androgens on tissues with steroidogenic capacity such as brain, testis and ovary. The objective of our study was to evaluate whether letrozole affects the development of the main reproductive control pathway of male and female spixs yellow-toothed cavy. For this, we considered body weight, testis, ovary and brain gain, spermatogenesis and folliculogenesis, as well as the enzymatic activity of cytochrome P450 aromatase in these tissues compared to experimental groups of males and females. The cavies received dilute letrozole orally (0,01 g/kg-1), once a week, until 30, 45, 90 and 120 days. Letrozole increased body weight, gonad and brain gain. Also, it impaired the formation of the testicular germinal epithelium and epithelium of ovary. Furthermore, the inhibitor may alter the neural fields related to the aromatization zones and changed the sites of aromatase in the gonads. We concluded that prolonged use of letrozole may result in an anabolic effect, male infertility, induce ovarian dysplasia in females, and alter the sites of aromatase activity. (AU)

• FAPESP's process: 13/22708-5 - Effect of letrozole in the hypothalamus and gonads of the agoutis during the stages of sexual development of male and female
• Grantee: Maria Angélica Machado Arroyo
• Support Opportunities: Scholarships in Brazil - Doctorate