title: Effects of parity and serum prolactin levels on the incidence and regression of DMBA-induced tumors in OFA hr/hr rats.
abstract: Prolactin (PRL) is a key player in the development of mammary cancer. We studied the effects of parity or hyperprolactinemia on mammary carcinogenesis in OFA hr/hr treated with 7,12-dimethylbenzanthracene. They were divided into three groups: nulliparous (Null), primiparous (PL, after pregnancy and lactation), and hyperprolactinemic rats (I, implanted in the arcuate nucleus with 17β-estradiol). The tumor incidence was similar in the three groups. However, a higher percentage of regressing tumors was evident in the PL group. Serum PRL, mammary development, and mammary β-casein content were higher in I rats compared to Null. The expression of hormone receptors was similar in the different groups. However, mammary tissue from PL rats bearing tumors had increased expression of PRL and estrogen alpha receptors compared to rats free of tumors. Our results suggest that serum PRL levels do not have relevance on the incidence of tumors, probably because the low levels of PRL in OFA rats are not further decreased by PL like in other strains. However, supraphysiological levels of PRL affect carcinogenesis. PL induces regression of the tumors due to the differentiation produced on the mammary cells. Alterations in the expression of hormonal receptors may be involved in progression and regression of tumors.
authors.affiliation: Laboratory of Hormones and Biology of Cancer, Institute of Medicine and Experimental Biology of Cuyo (IMBECU), CONICET, CCT-Mendoza, Avenida Adrián Ruiz-Leal s/n, CC855, 5500 Mendoza, Argentina.
authors.forename: Corina V
authors.identifier: 0000-0003-4127-2902
authors.initials: CV
authors.lastname: Sasso
authors.affiliation: Laboratory of Hormones and Biology of Cancer, Institute of Medicine and Experimental Biology of Cuyo (IMBECU), CONICET, CCT-Mendoza, Avenida Adrián Ruiz-Leal s/n, CC855, 5500 Mendoza, Argentina.
authors.forename: Flavia E
authors.identifier: 0000-0001-5607-156X
authors.initials: FE
authors.lastname: Santiano
authors.affiliation: Laboratory of Hormones and Biology of Cancer, Institute of Medicine and Experimental Biology of Cuyo (IMBECU), CONICET, CCT-Mendoza, Avenida Adrián Ruiz-Leal s/n, CC855, 5500 Mendoza, Argentina.
authors.forename: Constanza M
authors.initials: CM
authors.lastname: López-Fontana
authors.affiliation: Laboratory of Hormones and Biology of Cancer, Institute of Medicine and Experimental Biology of Cuyo (IMBECU), CONICET, CCT-Mendoza, Avenida Adrián Ruiz-Leal s/n, CC855, 5500 Mendoza, Argentina.
authors.forename: Virginia
authors.identifier: 0000-0002-1079-4663
authors.initials: V
authors.lastname: Pistone-Creydt
authors.affiliation: Institute of Sciences, Faculty of Medicine, German Clinique, University of Development, Santiago, Chile.
authors.forename: Marcelo E
authors.initials: ME
authors.lastname: Ezquer
authors.affiliation: Laboratory of Reproduction and Lactation, Institute of Medicine and Experimental Biology of Cuyo (IMBECU), CONICET, 5500 Mendoza, Argentina.
authors.forename: María B
authors.identifier: 0000-0003-4381-5368
authors.initials: MB
authors.lastname: Hapon
authors.affiliation: Laboratory of Reproduction and Lactation, Institute of Medicine and Experimental Biology of Cuyo (IMBECU), CONICET, 5500 Mendoza, Argentina.
authors.forename: Graciela A
authors.initials: GA
authors.lastname: Jahn
authors.affiliation: Laboratory of Hormones and Biology of Cancer, Institute of Medicine and Experimental Biology of Cuyo (IMBECU), CONICET, CCT-Mendoza, Avenida Adrián Ruiz-Leal s/n, CC855, 5500 Mendoza, Argentina.
authors.forename: Rubén W
authors.identifier: 0000-0002-8223-9140
authors.initials: RW
authors.lastname: Carón
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene / Q000633:toxicity*; D000818:Animals; D002273:Carcinogens / Q000633:toxicity*; D005260:Female; D008321:Mammary Glands, Animal / Q000378:metabolism / Q000473:pathology; D008325:Mammary Neoplasms, Experimental / Q000097:blood / Q000139:chemically induced / Q000473:pathology; D009363:Neoplasm Proteins / Q000097:blood*; D010298:Parity; D011247:Pregnancy; D011388:Prolactin / Q000097:blood*; D051381:Rats
chemical_list: D002273:Carcinogens; D009363:Neoplasm Proteins; D015127:9,10-Dimethyl-1,2-benzanthracene; D011388:Prolactin