PROLACTIN RECEPTORS IMMUNOHISTOCHEMISTRY AND APOPTOSIS OF MAMMARY GLANDS FROM LACTATING MICE MUS MUSCULLUS (LINNAEUS)

ABSTRACT

Lactation is essential for the growth and development of newborns. Drugs administered during lactation can alter the offspring development or damage the mammary glands changing the milk production. There are few studies about the evolution of prolactin receptors expression and on the presence of apoptotic cells in acinus of mammary glands from lactating mice, this is the aim of the present study. Mammary glands of female mice were obtained in the 19th day of pregnancy and in different days of lactation. It was evaluated: the number of acinus by microscopic field and number of cells by each acinus. The expression of prolactin receptors was identified trough immunohistochemistry, and the presence of apoptotic cells by using the TUNEL method. The presence of prolactin positive cells, discreet in the end of pregnancy, significantly increases already on the 1st day of lactation and remains high until weaning. The mammary gland involution, indicated by the increase in the number of apoptotic cells, starts around the 8th postnatal day and continues until weaning.

KEY WORDS:
Mammary gland; lactation; prolactin; immunohistochemistry; apoptosis.