Senior Scientist Emeritus, Inflammation & Chronic Disease
Ottawa Hospital Research Institute

Professor Emeritus, Obstetrics and Gynecology
University of Ottawa

Cross-appointed (retired), Cellular and Molecular Medicine
University of Ottawa

(Please note: Dr. Baltz retired in 2024 and is no longer accepting students or postdoctoral fellows)

My laboratory worked on mammalian oocyte growth and maturation and early embryo development. At the time a new life begins, the egg and embryo change very rapidly, virtually becoming a completely different organism every few hours. We were particularly interested in the physiological alterations that occur to accommodate the constantly changing nature of the egg and embryo and their implications for the health of the embryo and offspring. We wanted to understand the precisely-choreographed activation and deactivation of the array of transporters and other physiological mechanisms needed to supply the constantly changing needs of the egg and embryo during these earliest stages of development, and understand what can go wrong. Overall, we added to our knowledge of the physiological processes important to mammalian eggs and embryos at the very beginning of life. We believe that this type of research helps improve the health of babies and the treatment of infertility through research leading to the development of improved techniques for producing healthy oocytes and embryos. Dr. Baltz still maintains collaborations with active researchers and serves on scientific society committees and journal editorial boards.

Dr. Baltz received his B.A. in Physics from the University of Pennsylvania, a Ph.D. in Biophysics from The Johns Hopkins University, and postdoctoral training with Dr. John Biggers at Harvard Medical School. Dr. Baltz is now Associate Scientific Director and a Senior Scientist at the Ottawa Hospital Research Institute, and Professor in the Department of Obstetrics and Gynecology at the University of Ottawa, as well as being cross-appointed in the Department of Cellular and Molecular Medicine. He is a member of the Board of Directors of the Canadian Fertility and Andrology Society, where he serves as Treasurer. Dr. Baltz has received an Ontario Premier's Research Excellence Award, a James Shannon Award from the US National Institutes of Health, and has been a Medical Council of Canada Scholar. He has served as Director of the CIHR Training Program in Reproduction, Early Development, and the Impact on Health (REDIH), as Chair of the federal Stem Cell Oversight Committee, as a member of the CIHR Institute of Human Development, Child and Youth Health Institute Advisory Board, and as Director of the Program on Oocyte Health, a Strategic Initiative of the Canadian Institutes of Health Research (CIHR) Institute of Human Development, Child and Youth Health. Dr. Baltz is a specialist in the field of reproduction and developmental biology, where he has published extensively in the areas of preimplantation embryo development and egg development in the ovary.

AD Macaulay, CS Ortman, KRJ Moore, and JM Baltz (2023). Initial detachment of the mouse oocyte from the zona pellucida is mediated by metallopeptidase activity. Biology of Reproduction 108:81-97.

AK Tscherner, T McClatchie, AD Macaulay, and JM Baltz (2023). Relationship of quantitative RT-PCR to RNAseq transcriptome identifies mouse preimplantation reference genes. Biology of Reproduction 109:601-617.

T McClatchie, M Meredith, MO Ouédraogo, S Slow, M Lever, MRW Mann, SH Zeisel, JM Trasler, and JM Baltz (2017). Betaine is accumulated via transient choline dehydrogenase activation during mouse oocyte meiotic maturation. Journal of Biological Chemistry 292: 13784-13794.

S Richard and JM Baltz (2017). Preovulatory suppression of mouse oocyte cell volume-regulatory mechanisms is via signalling that is distinct from meiotic arrest. Scientific Reports 7:702,1-11.

AP Tartia, N Rudraraju, T Richards, MA Hammer, P Talbot, and JM Baltz (2009). Cell volume regulation is initiated in mouse oocytes after ovulation. Development 136: 2247-2254.

G FitzHarris and JM Baltz (2006).  Granulosa cells regulate intracellular pH of the murine growing oocyte via gap junctions: development of independent homeostasis during oocyte growth. Development 133:591-599.

CL Steeves, MA Hammer, GB Walker, D Rae, NA Stewart, and JM Baltz. (2003). The glycine neurotransmitter transporter GLYT1 is an organic osmolyte transporter regulating cell volume in cleavage-stage embryos. Proceedings of the National Academy of Sciences USA (PNAS) 100:13982-13987.