Comparative Effects of the Preventive Effect of Pregnancy, Steroidal Hormones, and hCG in the Transcriptomic Profile of the Rat Mammary Gland

Body condition of late pregnant gilts affects the expression of selected adipokines and their receptors in mammary fat and backfat tissues1

“…In pigs, PNPLA3 transcripts are observed in different tissues with its greatest expression in backfat (Chen et al, 2011). Russo and Russo (2013) found PNPLA3 transcripts in rat mammary glands, but they did not look for its presence in the mammary fat pad. When compared with virgin female rats, there was a downregulation of PNPLA3 gene expression in parenchymal tissue of late pregnant rats, suggesting a different transcriptional regulation between pregnant and nonpregnant rats (Russo and Russo, 2013).…”

“…Moreover, PRL was reported to affect adiponectin and leptin release from adipose tissue in rodents (Ben-Jonathan and Hugo, 2015). Adiponutrin was selected because it is expressed in the pig's subcutaneous adipose tissue (Chen et al, 2011), because its expression was shown in the rat mammary gland (Russo and Russo, 2013) and because leptin may be implicated in regulating PNPLA3 gene expression (Lake et al, 2005). Subcutaneous backfat tissue was also collected for gene expression analyses of ADIPOQ, LEP, PNPLA3, and PRL.…”

Mimicking pregnancy as a strategy for breast cancer prevention

“…TEBs are the least developed structures with the highest proliferative rates, characteristics that confer on them the highest susceptibility to carcinogenesis [26,27]. We counted the number of structures of the rat mammary gland and expressed them as a percentage of total mammary gland area (mm 2 ; Figure 2) [36]. Mammary glands from the control group were devoid of lob 2 and lob 3, while pregnancy, E+P pellets and hCG stimulated gland differentiation to reach the stage of lob 3.…”

“…The following is a summary of the materials and methods used in the study previously described [36]. To analyze the gene-expression profile induced by pregnancy and the treatments that mimic pregnancy (hCG and an E+P pellet), we treated 50-day-old virgin female Sprague–Dawley rats.…”

“…In this report, we summarize a previous study performed in our laboratory in which the gene-expression levels in the mammary glands of rats under different reproductive and hormonal conditions that have been shown to be protective against breast carcinogenesis (i.e., pregnancy, hCG and estrogen + progesterone [E+P]) [13,25–35] were compared with the gene-expression levels in the mammary glands of untreated rats [36]. Herein, the genes that we believe are essential for a common mechanism of protection among pregnancy, hCG and E+P, are emphasized, and we postulate a protective mechanism induced by hCG, which could represent an advantage of the use of this hormone as a prophylactic agent against breast cancer in high-risk women, due to its ability to induce additional differentiation of this organ.…”