Maternal metabolic and nutrient trafficking adaptations to lactation differ among lean and obese mice fed a high fat (HF) diet. Obesity is thought to impair milk lipid production, in part, by decreasing trafficking of dietary and de novo synthesized lipids to the mammary gland. Here, we report that de novo lipogenesis regulatory mechanisms are disrupted in mammary glands of lactating HF-fed obe...

Transforming growth factor (TGF)-beta1 and TGF-beta3 are normally expressed at high levels in the mammary gland during quiescence and at all stages of development, except lactation. Exogenously added TGF-beta1, -beta2, and -beta3 have been shown to regulate growth and differentiation of mammary epithelial cells in vitro and in vivo. TGF-betas signal through a heteromeric complex of type I and t...

It has been reported that twice-weekly i.p. injections of 4 mg phorbol for 10 weeks, after a single feeding of 6 mg dimethylbenz(a)anthracene (DMBA) in female Wistar rats, led to a significant augmentation of mammary adenocarcinoma incidence and of lymphatic leukemia incidence as compared to 6 mg DMBA alone. In an experiment reported here, in female Sprague-Dawley rats, using the same doses of ...

The pandemic caused by COVID19 triggered a new educational panorama, requiring teachers to show efficiency and creativity in teaching. virtual environment became the study space students had adapt distance classes continue school activities. Biology teaching benefits from strategies that promote relationship between theory practice, when based on modeling, it is perceived as an efficient resour...

Female rats of ten different inbred strains were tested for their susceptibility to 7, 12-dimethylbenz[a]anthracene (DMBA)-induced mammary adenocarcinogenesis. Five of these strains (OM, NSD, WF, LEWIS, BUFF) were demonstrated to be highly susceptible to DMBA exposure developing greater than 2 continuously growing, macroscopically detectable mammary adenocarcinomas/rat following gastric intubat...

The mammary gland goes through a coordinated series of developmental states during postnatal life in preparation for lactation. These changes ultimately reflect a changing endocrine environment alongside local alterations in the microenvironment. A longstanding assumption has been that estrogens serve as the first essential component for any of these developmental changes to be realized in the ...

Developmental stages of mammary glands influence their susceptibility to initiating events related to carcinogenesis. The "window of susceptibility" to mammary carcinogenesis is classically defined as the time in early puberty when the mammary gland morphology is most sensitive to initiation events. Administration of the polyaromatic hydrocarbon, 7,12-dimethylbenz(a)anthracene (DMBA), in a sing...

Activation of telomerase in human cancers is thought to be necessary to overcome the progressive loss of telomeric DNA that accompanies proliferation of normal somatic cells. According to this model, telomerase provides a growth advantage to cells in which extensive terminal sequence loss threatens viability. To test these ideas, we have examined telomere dynamics and telomerase activation duri...

Activation of telomerase in human cancers is thought to be necessary to overcome the progressive loss of telomeric DNA that accompanies proliferation of normal somatic cells. According to this model, telomerase provides a growth advantage to cells in which extensive terminal sequence loss threatens viability. To test these ideas, we have examined telomere dynamics and telomerase activation duri...

Insulin like growth factor-1 (IGF-1) stimulates increased proliferation and survival of mammary epithelial cells and also promotes mammary tumorigenesis. To study the effects of IGF-1 on the mammary gland in vivo, we used BK5.IGF-1 transgenic (Tg) mice. In these mice, IGF-1 overexpression is controlled by the bovine keratin 5 promoter and recapitulates the paracrine exposure of breast epitheliu...