Cornell University Animal Science

Patricia A. Johnson   -   Professor

PhD from Cornell University

 
Graduate fields:      Animal Science, Molecular & Integrative Physiology
 
Area(s) of interest:      endocrinology, comparative reproductive physiology
 
Teaching:

• Fundamentals of Endocrinology - AS 427
• Current Concepts in Reproductive Biology (co-teach) - BioAP 757

Professional Organizations:

• Society for the Study of Reproduction
• Endocrine Society

 
 

Current Research:

There are two objectives of the ongoing research in my lab. Our first goal is to understand the process of follicle selection and development in the hen. The features of avian follicle development make the hen an ideal model for understanding the process of regulation of follicular recruitment. It is possible to study the production of a specific hormone by an individual follicle. We have studied the ovarian hormones inhibin, activin and anti-mullerian hormone as well as the oocyte-specific factor, GDF9. By understanding the interaction of the somatic cells and the oocyte in a species in which preovulatory development is so ordered and predictable, it may be possible to generalize these findings to other domestic animal species as well. A fundamental understanding of follicular recruitment is essential to maximizing reproductive efficiency, especially in turkeys and broiler breeder hens where egg production is not optimal. Our second research goal relates to the development and characterization of the chicken as a model for human ovarian cancer. There is no animal model, other than the hen, which spontaneously develops ovarian cancer with a high incidence. Previous studies, as well as our own data, show that hens develop ovarian cancer with a striking similarity to that found in human females. The main cause of the lethality of ovarian cancer in women is the fact that it is usually diagnosed at an advanced stage. The availability of an animal model will increase the chance of finding a marker for early diagnosis. In addition, an animal model will permit the testing of pharmaceuticals that may decrease the growth of this cancer. Finally, selected genomic analysis of hens with and without the disease may reveal a difference that underlies differential susceptibility to ovarian cancer.

Selected Recent Publications:

Urick, M.E., Giles, J.R. and P.A. Johnson. VEGF expression and the effect of NSAIDS on ascites cell proliferation in the hen model of ovarian cancer. Gynecological Oncology, accepted, in press.

Johnson, PA, ME Urick, TR Kent and JR Giles. Expression and regulation of anti-mullerian hormone in the hen. Biology of Reproduction, 78:13-19, 2008.

Urick, M.E. and P.A. Johnson. Cyclooxygenase 1 and 2 mRNA and protein expression in the Gallus domesticus model of ovarian cancer. Gynecological Oncology, 103:673-678, 2006.

Giles, J. R., L. M. Olson and P.A. Johnson. Characterization of Ovarian Surface Epithelial Cells from the Hen – A Unique Model for Ovarian Cancer. Exper. Biol. and Medicine, 231:1718-1725, 2006.

Johnson, P.A. and J.R. Giles. Use of genetic strains of chickens in studies of ovarian cancer. Poultry Science 85:246-250, 2006.

Johnson, P.A., J.R. Woodcock and T.R. Kent. Effect of activin A and inhibin A on expression of the inhibin/activin Beta-B-subunit and gonadotropin receptors in granulosa cells of the hen. Gen Comp Endocrinol. 147:102-107, 2006.

Correa, S.M., E. Adkins-Regan and P.A. Johnson. High progesterone during avian meiosis biases sex ratios toward females. Biology Letters, 1(2):215-218, 2005.

Johnson, P.A., M.J. Dickens, T.R. Kent and J.R. Giles. Expression and Function of Growth Differentiation Factor-9 in an Oviparous Species, Gallus domesticus. Biol Reprod 72:1095-1100, 2005.