Endocrine Abstracts

Introduction: The human masculinisation programming window (8–14 weeks of gestation) sees testis-derived androgen drive the foetus towards a male phenotype. However, there are few systematic studies of human foetal gonad development.

Aim: To conduct a pilot analysis of the foetal gonadal proteome at the end of the masculinisation programming window (13–14 weeks of gestation).

Methods: Twenty-eight electively terminated foetuses (13–14 weeks of gestation: REC04/S0802/21) were divided into four groups (n=7/group) based on foetal sex and maternal smoking status. Protein (and RNA) were extracted from whole gonads and 2D difference in-gel electrophoresis (DIGE) and SameSpots Software were used to analyse the proteomes. Proteins were identified in 18 consistently altered protein spots by LC–MS/MS and followed up by qPCR (same 28 foetuses plus 44 foetuses reported in the literature).

Results: There were no significant differences between foetal or maternal ages and morphometrics (except testes heavier than ovaries; P<0.05). Of 448 protein spots included in the study, 147 were significantly (P<0.05) different between groups (1.2- to 13.7-fold). Of these 55 were over-expressed in males, 76 in females and maternal smoking induced or abolished sex differences in 16 and 32 respectively. SERPINB9, KRT8, and KRT85 were higher in females; VIM, ECHS1, FDXR, VCL, EZR, HSPD1, IDH1, PRDX4, CYP11A1, PRDX3, TPI, GDI, UCHL1, IDI1, and GSTA1 higher in males. Transcript levels encoding these proteins were also significantly different between sexes. 14 proteins significantly associated in a network of drug metabolism and endocrine system development/function. Protein differences suggest increased cell proliferation, steroid synthesis/metabolism, and oxidative stress in the testis, consistent with known differences in testis and ovary developmental biology.

Conclusions: Proteomic analysis of abundant proteins showed that 29% protein spots have sex-specific expression. In-depth proteomic analysis of proteomes is likely to reveal further insight into sex-specific mechanisms and pathways in each type of human foetal gonad.