Progesterone Receptors and Proliferation in the Bitch Uterus during Different Stages of the Oestrous Cycle

Abstract

Immunopresence of the progesterone receptors (PR) and proliferative activity in the bitch uterus were studied during different stages of the oestrous cycle. Uterine samples were collected at 4 different stages of the oestrous cycle; prooestrus, oestrus, dioestrus and anoestrus. Immunohistochemistry was used to evaluate the localization and to
semiquantitate PR and uterine proliferation by using monoclonal antibodies to the PR and the proliferative marker, Ki-67 respectively. The results showed that PR and Ki-67 levels were highest during prooestrus and oestrus while they were low at other stages. However, a significant difference was observed only in the surface epithelium for Ki-67 immunostaining. A positive correlation was found between PR positive and Ki-67 positive cells in the surface epithelium. The results from the present study strengthen previous finding that the presence of PR and uterine proliferation differ with oestrous cycle stages and among different uterine compartments; and suggested a possible relationship between the PR and the proliferative marker, Ki-67 in the surface epithelium of the bitch uterus.