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Chemical sympathectomy blocks androgen biosynthesis during prepuberty
A A Rosa-e-Silva1, M A Guimarães, T L Lamano-Carvalho
1Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brasil.
Summary
Guanethidine (GUA) treatment in male rats disrupts testicular androgen production during puberty. This suggests sympathetic innervation plays a role in modulating steroid biosynthesis pathways.
Area of Science:
- Reproductive Endocrinology
- Neuroendocrinology
- Developmental Biology
Background:
- The sympathetic nervous system innervates the testes, but its role in regulating steroidogenesis during sexual development is not fully understood.
- Androgen biosynthesis is crucial for male sexual maturation and is tightly regulated by hormonal and neural factors.
Purpose of the Study:
- To investigate the effect of guanethidine (GUA), a sympathetic neurotoxin, on testicular steroid levels during prepubertal and early pubertal development in male rats.
- To determine if sympathetic innervation influences androgen production and the specific steps involved in the steroidogenic pathway.
Main Methods:
- Male Wistar rats were treated with GUA (5 and 10 mg/kg/day) for 20 days.
- Testes were collected at 41 (prepubertal) and 51 (early pubertal) days of age.
- Testicular concentrations of progesterone (P), androstenedione (A), and testosterone (T) were quantified.
Main Results:
- GUA treatment (10 mg/kg) in prepubertal rats significantly increased progesterone levels while decreasing androstenedione and testosterone.
- In early pubertal rats, GUA (10 mg/kg) elevated progesterone levels.
- Both GUA doses reduced testicular testosterone concentrations in 41-day-old rats.
Conclusions:
- Sympathetic innervation of the testis modulates androgen biosynthesis during sexual maturation.
- GUA disrupts androgen production by acting on specific steps in the steroidogenic pathway.
- The dose-dependent blockage of androgen biosynthesis by GUA in the prepubertal stage highlights the critical role of sympathetic nerves in male sexual development.