Reproduction Abstracts

Cell ablation is a powerful technique for examining the role of a particular cell type in organ development and function. The utility of the technique is dependent upon the ablation being specific to one cell type and for those of us interested in the testis we have been fortunate that methods have existed for some time to ablate the germ cells and the Leydig cells. Recently we have also developed a transgenic mouse model which expresses the diphtheria toxin receptor (DTR) spe...

Introduction: Tamoxifen inducible Cre systems have been used to study development specific roles of genes in the testis as they allow tight temporal control of genetic manipulation. However, tamoxifen is an anti-estrogen that competitively binds estrogen receptors. Despite the antagonistic properties of tamoxifen, it also acts as a weak estrogen agonist, hence exerting estrogenic effects in a tissue and cell specific manner. Given the duality of tamoxifen function and the impo...

Introduction: Leydig cells (LCs), the key producer of testosterone (T) in the testis, are affected by various factors such as hormone stimulation. There are various testicular cells that also affect LC function such as testicular interstitial macrophages (TIMs). TIMs are immune factor-producing cells, located adjacent to the LCs, sharing a close physiological and functional relationship. TIMs are associated with development and function of LCs. Ablation of TIMs have shown to i...

Androgen receptor (AR) is expressed by testicular somatic cells including steroidogenic Leydig cells (LC). Its role in LC is ill defined, with hypotheses based on evidence from total androgen receptor knockout models implying that LC AR is responsible for final LC number, regulation of steroidogenic enzyme expression and LC maturation.To better define the role of AR in LC, we generated a mouse line with a LC specific ablation of AR (LCARKO) using the Cre...

Sertoli cells (SC) are key initiators of testis development and have a fundamental role in spermatogenesis. However, it is uncertain how an acute reduction in SC number, in a hormone independent-manner at key points in development or adulthood, will impact testis function.To induce acute SC-ablation at key points of testicular development, we used Cre-loxP recombinase technology and the expression of Diphtheria toxin and its receptor. We utilized these l...

The aging of western societies, and the associated increase in obesity, brings with it an increase in prevalence of disorders such as metabolic syndrome which are associated with reduced androgen levels in men. As Leydig cells are the source of androgens in the male, establishing the mechanisms which control Leydig cell development and function is crucial to our understanding of aging and male health. Sertoli cells regulate testicular fate in the differentiating gonad and are ...

Production of testosterone by testicular Leydig cells is under tight regulation by the hypothalamic – pituitary – gonadal (HPG) axis. GnRH, secreted by the hypothalamus, stimulates secretion of LH from the pituitary. LH will then stimulate testosterone production in the Leydig cells, which will feedback to the hypothalamic-pituitary element to inhibit LH secretion.Previously it was accepted that testosterone exerted its negative feedback action...

Introduction: Adult male testosterone levels are influenced by fetal events, but how is unknown, as adult Leydig cells (ALC) do not differentiate until puberty. We hypothesised that adult Leydig stem cells are present in the fetal testis, and are susceptible to programming by fetal androgen exposure. We have shown that ALC derive from interstitial cells that express chicken ovalbumin upstream promoter transcription-factor II, essential postnatally for ALC development, and andr...