Date of Award

Fall 2006

Project Type

Thesis

Program or Major

Animal Science

Degree Name

Master of Science

First Advisor

Paul Tsung

Abstract

To study dynamic in vivo biochemical changes within the corpus luteum (CL) during luteolysis, a physiological model mimicking the onset of natural luteolysis was established, in which sheep received sequential systemic pulses of PGF2alpha (20ug/min/lhr) at mid-luteal phase of the estrous cycle. We previously demonstrated that after one pulse of PGF2alpha, the protein levels of extracellular matrix (ECM) regulators, tissue inhibitors of metalloproteinases (TIMPs) -1 and -2 decreased dramatically within one hour of PGF2alpha infusion, while matrix metalloproteinase (MMP)-2 activity increased 4 hrs post infusion. In summary, the early and dramatic decrease in TIMP-1 and TIMP-2 proteins, accompanied by an increase in MMP-2 activity, indicate an extension and amplification by the second pulse of PGF2alpha on regulators of the ECM within the CL. These findings confirm a critical role for regulators of the ECM in mediating both structural and steroidogenic changes during physiological PGF2alpha-induced luteolysis in sheep. (Abstract shortened by UMI.).

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