Quantification of IGF-I expression in ovine mammary gland during lactation and pregnancy.

DALLARD BE, SALVETTI NR, REY V, LORENTE JA, PASTOR RP, GODOY E C, ROMANO GS.

La Plata, Argentina

Congreso; IX Congreso Argentino de Ciencias Morfológicas; 2004

Facultad de Ciencias Veterinarias. Universidad Nacional de La Plata

The insulin-like growth factor I (IGF-I) is growth stimulating of mammary epithelial cells in vivo and in vitro, and in synergism with mammogenic hormones, IGF-I regulates the mammary development. The aim of this study was to identify and quantify IGF-I using immunohisctochemistry in ovine mammary glands during lactation and pregnancy, and to establish differences in IGF-I expression. The biopsies were carried out in sheep at 10 prepartum days and 5, 15, 25, 70, 90, 120 pospartum days. The samples were fixed in 10 % buffered formaline into accord to routine protocols. Immunohistochemical methods were used for IGF-I detection (streptavidin-peroxidase). Images were analyzed with Image Pro-Plus 4.1.0.1® program. The IGF-I expression was mainly associated with the secretory epithelium of mammary gland. The highest percentage (%) of reaction was observed during lactogenesis and galactopoiesis with a distinct immunoreactivity for IGF-I in lactocytes (days 1 to 25 of lactation). The lowest expression of IGF-I was found in ewes with more than 120 days of lactation, and differed significantly (p<0.05) with the % of IGF-I expression obtained during early lactation and advanced pregnancy. The results lead us to conclude that the IGF-I expression may play a role in mammary development and remodeling in ovine mammary gland during advanced pregnancy, lactation and involution.