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Sexual dimorphism in the neonatal gonad
I A Hughes1, N Coleman, S Faisal Ahmed
1Department of Paediatrics, University of Cambridge, Addenbrooke's Hospital, UK.
Acta Paediatrica (Oslo, Norway : 1992). Supplement
|April 2, 1999
Summary
Neonatal gonads exhibit sexual dimorphism, developing into testes or ovaries early in embryogenesis. Key differences in morphology and endocrine function emerge between fetal and neonatal testes and ovaries.
Area of Science:
- Developmental Biology
- Reproductive Endocrinology
- Genetics
Background:
- Neonatal gonads are sexually dimorphic, with distinct morphological and endocrine characteristics established by birth.
- The process of sexual dimorphism begins early in embryogenesis, involving complex genetic and molecular mechanisms.
Purpose of the Study:
- To review the morphological changes and endocrine functions of developing gonads.
- To highlight critical differences in fetal and neonatal gonadal function between sexes.
Main Methods:
- Review of existing literature on gonadal development and sexual differentiation.
- Comparative analysis of morphological and endocrine characteristics of fetal and neonatal testes and ovaries.
Main Results:
- Testes exhibit early histological definition, multiple determining genes, delayed germ cell maturation, and early steroid secretion.
- Ovaries display a prolonged monomorphic state, likely one determining gene, germ cells in meiotic arrest, and delayed receptor expression.
- Significant differences observed in hormone secretion (testosterone vs. estradiol), cell prominence (Leydig/Sertoli vs. follicles), and gene expression patterns.
Conclusions:
- Sexual dimorphism in gonads is a complex process involving genetic and endocrine factors.
- Distinct developmental trajectories and functional characteristics differentiate testes and ovaries from the fetal stage through to neonatal life.
- Understanding these differences is crucial for comprehending reproductive health and potential disorders.