Professor Alan Tilbrook

Director MBIO Graduate School

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Background

Alan Tilbrook was awarded a BSc (Agric.) Hons and PhD from the University of Western Australia. His PhD studies were in the areas of reproductive physiology and behaviour. After completing his PhD he worked in the (then) School of Agriculture and Forestry at the University of Melbourne before moving to the Victorian Institute of Animal Science as a research scientist conducting research on neuroendocrinology, endocrinology and behaviour on a range of species. He joined the Department of Physiology at Monash University in October 1992 and was Deputy Head of Department from July 2006 to March 2009. He heads the Neuroendocrinology and Behaviour Research Laboratory.

Research Interests

Alan Tilbrook has a multidisciplinary and integrative approach to research that involves national and international collaborations. His research focuses on the behavioural and physiological consequences of stress and the mechanisms underlying regulation of reproductive function and lactation. A key area of this research is aimed at determining the mechanisms by which different physiological states influence stress responsiveness. This includes lactating females which show reduced stress responses and females with different levels of fat. Alan’s research showed that animals cope differently to stress according to weight, such that; greater adiposity leads to greater stress responses compared those seen in lean animals. This finding has important implications for stress-induced diseases that are exacerbated in overweight or obese animals as well as illnesses of the human condition, of which Alan plans to address with clinical collaborations. A major area of research has shown sex differences in response to stress and on the impact of stress on reproduction and has made major advancement in our understanding of the impact of stress and the role of the glucocorticoid cortisol on the endocrine regulation of reproduction in the female. Recently, this research demonstrated that stress impacts female sexual behaviour, such that stress reduces both the ability of females to attract males and their motivation to mate. This finding provides important insight regarding the success of reproduction in animals and humans. Research is currently underway to explain the effects of maternal stress on offspring development. Previously, Alan’s research contributed to identifying the hormonal interactions of the male reproductive axis by characterising the roles of inhibin and testosterone in the negative feedback regulation of the secretion of the gonadotrophins.

Grants Held

Collaborations

Alan Tilbrook has long-standing international and national multidisciplinary collaborations with 7 institutions; Monash University, University of Adelaide, Department of Primary Industry Victoria, University of Melbourne, University of Michigan, USA, University of Bristol, UK University of California (Berkeley) USA.

Research Training

Alan Tilbrook places strong value on research training and development of leadership in students and postdoctoral researchers. He has mentored 5 postdoctoral researchers and 29 research students. Recent PhD completions include:

• Dr Anne Turner (finished1999) was the first ranked PhD student in Physiology and was nominated for the Mollie Holman Doctoral Medal for best PhD thesis in the Faculty of Medicine, Nursing and Health Sciences. The ground breaking research of her PhD discovered the effects of stress on reproduction in female pigs. She was internationally recognised at the International Congress on Farm Animal Endocrinology in Hungary in 2004 and the International Conference of Pig Reproduction in The Netherlands in 2005 from which 2 invited reviews resulted including Domestic Animal Endocrinology. 2005; 29:398-410; Society of Reproduction and Fertility Supplement 2006; 62:191-203.
• Dr Catherine Stackpole made a critical contribution to understanding the mechanisms of the effects of stress on the secretion of the gonadotrophins from the anterior pituitary gland (Biology of Reproduction 2004, 69 1158-1164; Endocrinology 2006; 147:5921-5931).
• Dr Elizabeth Rivalland identified central pathways active during stress in males and females (Neuroscience 2005; 132:755-766; Neuroendocrinology 2006; 84:1-13; Neuroscience 2007; 145:1048-1058).
• Dr Bree Pierce delineated the effects of stress and cortisol on the secretion of reproductive hormone and sexual behavior (Neuroendocrinology 2008 in press; Endocrinology 2008, in press; Hormones and Behavior in press). Her research has been recognized by the Faculty of Medicine, Nursing and Health Sciences as being worthy of a media press release.

Acaedemic Interests

Alan has recently developed the Graduate Program in Biomedical Sciences at Monash University that will be delivered in the recently formed Mbio Graduate School of which Alan is the Director. The principal aim of this program is to extend the current Higher Degrees by Research training to enrich and broaden the experience of students and better prepare them for a range of careers.

Some Key Publications

1. Oakley AE, Breen KM, Clarke IJ, Karsch FJ, Wagenmaker ER & Tilbrook AJ 2008. Cortisol decreases GnRH pulse frequency in follicular phase ewes: permissive role of ovarian steroids Endocrinology Published online doi:doi:10.1210/en.2008-0587 18^th September 2008.
2. Wagenmaker, ER, Breen, KM, Oakley, AE, Tilbrook, AJ & Karsch, FJ 2008. Psychosocial stress inhibits amplitude of gonadotropin-releasing hormone pulses independent of cortisol action on the type II glucocorticoid receptor. Endocrinology In press 22^nd September 2008.
3. Pierce, BN, Hemsworth, PH, Rivalland ETA, Wagenmaker ER, Morrissey AD, Papargiris MM, Clarke IJ, Karsch FJ, Turner AI & Tilbrook AJ 2008. Psychosocial Stress Suppresses Attractivity, Proceptivity and Pulsatile LH Secretion in the Ewe Hormones and Behavior  54 424-434.
4. Tilbrook, AJ Rivalland, ETA, Turner, AI, Lambert, GW & Clarke, IJ 2008. Responses of the hypothalamo-pituitary adrenal axis and the sympathoadrenal system to isolation/restraint stress in sheep of different adiposity. Neuroendocrinology 87 193-205.
5. Rivalland ETA, Clarke IJ, Turner AI, Pompolo S & Tilbrook AJ 2007. Isolation and restraint stress results in differential activation of corticotrophin-releasing hormone and arginine vasopressin neurones in sheep. Neuroscience 145, 1048-1058.
6. Stackpole, CA, Clarke IJ, Breen, KM, Turner, AI, Karsch FJ & Tilbrook AJ 2006 Sex difference in the suppressive effect of cortisol on pulsatile secretion of luteinizing hormone in sheep. Endocrinology 147, 5921-5931.
7. Tilbrook AJ, Turner AI, Ibbott MD & Clarke IJ 2006 Activation of the hypothalamo-pituitary adrenal axis by isolation and restraint stress during lactation in ewes: effect of the presence of the lamb and suckling.  Endocrinology 147, 3501-3509.
8. Tilbrook, AJ & Clarke IJ 2006 Neuroendocrine mechanisms of innate states of attenuated responsiveness of the hypothlamo-pituitary adrenal axis to stress.  Frontiers in Neuroendocrinology 27, 285-307 [Invited Review].
9. Tilbrook AJ & Clarke 2001. Negative feedback regulation of the secretion and actions of GnRH in Males.  Biology of Reproduction 64, 735-742.  [Invited Review].
10. Tilbrook AJ, Canny BJ, Serapiglia MD, Ambrose TJ, & Clarke IJ 1999. Suppression of the secretion of luteinizing hormone due to isolation/restraint stress in gonadectomized rams and ewes is influenced by sex steroids. Journal of Endocrinology 160, 469-481.
11. Tilbrook AJ, de Kretser DM & Clarke IJ 1993. Human recombinant inhibin A and testosterone act directly at the pituitary to suppress plasma concentrations of FSH in castrated rams. Journal of Endocrinology 138, 181-189. 
12. Tilbrook AJ, de Kretser DM, Cummins JT & Clarke IJ 1991. The negative feedback effects of testicular steroids are predominantly at the hypothalamus in the ram. Endocrinology 129, 3080-3092.