I am a geneticist determining the molecular mechanisms that underlie gonad (testis and ovary) development and dysgenesis in patients with disorders of sexual development.
Impairment of virilisation is one of the most common developmental defects in humans, yet over half the cases cannot be explained by our current knowledge. Studies of these processes is hindered because in most mammals virilisation occurs in the early fetus. Our recent studies using marsupials, where virilisation occurs after birth show that this process is mediated by 5-alpha-androstanediol, a hormone with previously undetermined physiological function. We will conduct experiments using tammar ....Impairment of virilisation is one of the most common developmental defects in humans, yet over half the cases cannot be explained by our current knowledge. Studies of these processes is hindered because in most mammals virilisation occurs in the early fetus. Our recent studies using marsupials, where virilisation occurs after birth show that this process is mediated by 5-alpha-androstanediol, a hormone with previously undetermined physiological function. We will conduct experiments using tammar wallabies and rabbits, to test 3 hypotheses about 5-alpha-androstanediol and specific enzymes in the developing reproductive tissues that either convert this hormone to active and inactive forms. The results of these experiments will direct testing for corresponding gene mutations in our collection of over 200 specimens from patients with defects of virilisation (pseudohemaphroditism) whose causes are still unknown. It is our expectation that the findings in these studies will provide insight not only into the pathways by which testicular hormones masculinize the developing male, but will also explain instances of male pseudohemaphroditism of unknown aetiology in humans.Read moreRead less
Mechanisms Of Testosterone Action On The Male Pelvic Autonomic Nervous System: The Role Of Estrogens
Funder
National Health and Medical Research Council
Funding Amount
$417,750.00
Summary
The aim of this project is to understand how the circulating hormone, testosterone, affects the autonomic nervous system in adult males. We are particularly interested in the effects this hormone has on the nerve supply of the urogenital organs, ie. the lower urinary tract and reproductive organs. We have already found that many different parts of this pelvic autonomic nervous system are androgen-sensitive, and if the levels of hormones drop significantly, then many properties of the neurons cha ....The aim of this project is to understand how the circulating hormone, testosterone, affects the autonomic nervous system in adult males. We are particularly interested in the effects this hormone has on the nerve supply of the urogenital organs, ie. the lower urinary tract and reproductive organs. We have already found that many different parts of this pelvic autonomic nervous system are androgen-sensitive, and if the levels of hormones drop significantly, then many properties of the neurons change. This is likely to impact negatively on reflexes like penile erection, prostate secretion and propulsion of seminal fluid. Our recent experiments suggest that many of these actions may be caused by testosterone acting in a way that does not involve the typical activation of its receptor molecule (the androgen receptor) and we think it is very likely that it is first converted by some pelvic autonomic neurons into estradiol. We have recently shown that estradiol has potent actions on signalling cascades in these neurons, and that many of the neurons make estrogen receptors. It is also possible that testosterone causes the release of growth factors from the organs, and these growth factors cause changes in their nerve supply. We will investigate both of these possibilities. The outcomes of this study will be relevant for understanding how pelvic autonomic reflexes are affected by endocrine disorders, ageing and various drugs that act on the endocrine system. Our results may also be useful for designing drugs that act on the endocrine system but with less side-effects on the nervous system.Read moreRead less
The Role Of MiRNAs In The Regulation Of Sperm Maturation
Funder
National Health and Medical Research Council
Funding Amount
$396,157.00
Summary
Male infertility is an extremely common condition affecting 1 in 20 Australian men. One of the major reasons for this pathology is that the spermatozoa have lost their ability to recognize the egg, a function that is acquired during epididymal maturation. In this project we shall investigate the regulation of epididymal sperm maturation and thus provide new and powerful insights into the causes of male infertility, with practical implications for diagnosis and treatment of this condition.
Hypospadias is one of the most common developmental defects in humans, yet over two thirds of the cases cannot be explained. Our recent studies using marsupials show that this process is mediated by 5-alpha-androstanediol, a hormone with previously undetermined physiological function. This study will provide novel data on the interactions of the genes and hormones that will inform our understanding of this common developmental defect of male development
Cysteine-rich Secretory Protein Regulation Of Ion Channels In Male Fertility And Prostate Cancer
Funder
National Health and Medical Research Council
Funding Amount
$474,309.00
Summary
Diagnosis of the precise causes of male infertility and the development of male contraceptives requires improved understanding of sperm function. The Cysteine-Rich Secretory Proteins (CRISPs) are produced in the male reproductive tract where they regulate sperm function. Our project will demonstrate the essential requirement for CRISPs in sperm function and investigate their role in other tissues of the reproductive tract, including the prostate where they may be involved in prostate cancer.
Understanding The Molecular Basis Of Epididymal Maturation: How Does The Epididymis Modify Spermatozoa, Allowing Them To Recognise The Egg ?
Funder
National Health and Medical Research Council
Funding Amount
$585,898.00
Summary
Male infertility is a significant clinical problem affecting one in twenty Australian men. A common feature of this condition is the sperm’s inability to recognize the egg. Sperm gain this property as they transit an organ known as the epididymis. We have produced genetically modified mice with a specific epididymal defect that prevents sperm-egg recognition. This study will examine the structure of these defective sperm to generate new insights into the molecular basis of sperm-egg interaction.
Understanding Sperm Motility For Infertility And Contraceptive Purposes
Funder
National Health and Medical Research Council
Funding Amount
$451,716.00
Summary
Male infertility is a significant clinical problem affecting one in twenty Australian men. The most common feature associated with this condition is defects in sperm motility. Regulation of sperm motility occurs through the epididymis and upon ejaculation. This study will examine how two kinases, essential for flagella bending, regulate sperm motility. Through the tools developed, we will investigate further defectives in infertile individuals with impaired sperm motility.