Spectrophotometry in the Far Ultraviolet

Elias, Joel J.

doi:10.1126/science.126.3278.842-a

Cited by 112 publications

(36 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Explants of mouse mammary fat pads were prepared from 4-to 6-month-old female virgin BALB/c mice as described (3). The animals used were either normal intact virgin mice or virgin mice that had the parenchyma surgically removed at 3 weeks of age, leaving a fat pad with only stromal tissue (cleared fat pads; ref.…”

Section: Methodsmentioning

confidence: 99%

“…1 and 2). Extensive studies (3-10) in fragment organ culture using mammary tissue from either mouse or rat under defined, serum-free conditions demonstrated that insulin (5, 6), prolactin (3)(4)(5)(6)(7)(8)(9)(10), and a glucocorticoid, usually cortisol (7-10), were required for the accumulation of casein protein and mRNA. Whole gland organ culture studies (11-13) have substantiated this requirement for the three hormones.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Linoleic acid, but not cortisol, stimulates accumulation of casein by mouse mammary epithelial cells in serum-free collagen gel culture.

Levay‐Young

Bandyopadhyay²,

Nandi³

1987

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

A two-step culture system has been developed to analyze the role of hormones in casein accumulation by mammary epithelial cells obtained from adrenaiectomized and ovariectomized adult virgin mice. In the first step cells are grown inside collagen gel in medium containing insulin, epidermal growth factor (EGF), and linoleic acid for 9 days; these conditions stimulate very little casein accumulation. Following this growth phase the gels are released to float in medium containing insulin, prolactin, and linoleic acid. During this second phase the mammary cells will accumulate large amounts of casein, but only in the simultaneous presence of insulin, prolactin, and linoleic acid; in the absence of linoleic acid casein accumulation is greatly reduced. The casein accumulation is not dependent on the presenceofthe glucocorticoid cortisol and will occur in spite of the presence of the antiglucocorticoid agent RU 38 486. To determine if the response to cortisol observed in organ culture by other investigators might be mediated by stromal cells, epithelial cells were grown in collagen gel under fatty acid-free conditions and then cocultured with explants of mammary fat pads from adult virgin mice with or without mammary parenchyma. The cocultures were performed in fatty acid-free medium containing insulin and prolactin with or without cortisol. In the majority of experiments the mammary epithelial cells in the collagen gel accumulate more casein in the presence of cortisol than in its absence, irrespective of the presence of mammary parenchyma in the explant. Thus, mammary epithelial cells are directly dependent on insulin and prolactin for casein accumulation and indirectly dependent on cortisol by means of its effect on the stromal cells. This cortisol effect may be to cause release into the medium of linoleic acid or a metabolic product of linoleic acid from the stromal cells.Despite its long history, the study of the effects of hormones and growth factors on mammary epithelium in culture has not fully defined the roles of these substances in mammary differentiation (for review, see refs. 1 and 2). Extensive studies (3-10) in fragment organ culture using mammary tissue from either mouse or rat under defined, serum-free conditions demonstrated that insulin (5, 6), prolactin (3)(4)(5)(6)(7)(8)(9)(10), and a glucocorticoid, usually cortisol (7-10), were required for the accumulation of casein protein and mRNA. Whole gland organ culture studies (11-13) have substantiated this requirement for the three hormones.Fewer experiments to examine this requirement for glucocorticoid have been performed in cell culture, even though cell culture has become widely used to study differentiation in mammary epithelial cells. Casein accumulation and secretion in cell culture were demonstrated by Emerman et al. in 1977 (14) using cells obtained from midpregnant mice and cultured on top of collagen gel. Casein secretion in this system has been repeatedly shown to be dependent on the presence of insulin, prolactin, and glucocortic...

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Linoleic acid, but not cortisol, stimulates accumulation of casein by mouse mammary epithelial cells in serum-free collagen gel culture.

Levay‐Young

Bandyopadhyay²,

Nandi³

1987

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…This indicated that the loss of differentiated expression seen in culture was reversible. Oran culture model systems were instrumental in defining the basic hornonal requirements for milk-specific gene expression in culture (21)(22)(23)(24). Isolated epithelia plated onto plastic substrata and cultured in the presence of lactogenic hormones (i.e, prolactin, insulin, hydrocortisone), however, fail to respond substantially when compared to explant cultures.…”

Section: Appropriate Ecm Is Necessary For the Functional Differentiatmentioning

confidence: 99%

Regulation of Functional Cytodifferentiation and Histogenesis in Mammary Epithelial Cells: Role of the Extracellular Matrix

Bissell¹,

Ram²

1989

Environmental Health Perspectives

View full text Add to dashboard Cite

Primary mammary epithelial cells provide a versatile system for the study of hormone and extracellular matrix (ECM) influences on tissue-specific gene expression. We have characterized the formation of aveolarlike morphogenesis and mammary-specific functional differentiation that occur when these cells are cultured on a reconstituted basement membrane (EHS). Cells cultured on EHS exhibit many ultrastructural and biochemical features indicative of polarized and functionally differentiated mammary epithelium in vivo. The increased expression and specific vectorial secretion of milk proteins into lumina formed in culture are accompanied by large increases in milk protein mRNA expression. However, when individual ECM components are tested, smaller increases in milk protein mRNA are measured on heparan sulfate proteoglycan (HSPG) and laminin, and these responses are not associated with full functional cytodifferentiation or histotypic configuration. This indicates that multiple levels of regulation are involved in mammary-specific gene expression, and that in addition to individual ligand requirements cooperative interactions between various ECM molecules and cells are necessary for functional differentiation in culture. We have also shown that endogenous production of ECM molecules and changes in cell geometry are correlated with changes in functional and histogenic gene expression. We have previously proposed a model of cell-ECM interactions that is consistent with these data.

show abstract

“…The a-lactalbumin genes from man and rat have been completely sequenced (66) The first model system for the study of mammary growth and differentiation in vitro was reported in 1957 by Elias (68); this mammary explant culture system has been widely used over the years. A whole mammary gland culture system has been established by Ichinose and Nandi (69); more recently, several methods for primary culture of mammary epithelial cells have been developed.…”

Section: Biochemical Markers Of Differentiation In Vitromentioning

confidence: 99%

Growth Control and Differentiation in Mammary Epithelial Cells

Borellini¹,

Oka²

1989

Environmental Health Perspectives

View full text Add to dashboard Cite

Growth and differentiation of the mammary gland are controlled by various hormones and other environmental factors The role of hormones and growth factors in mammary development is discussed with regard to animal species, physiological stages, and the various experimental systems in vitro. In the female embryo, mammary morphogenesis is induced by the mesenchyme and is hormone independent, whereas androgens cause the partial necrosis of mammary epithelium in the male. Ductal growth during adolescence requires estrogen and prolactin or growth hormone. During pregnancy, progesterone participates in the development of the lobuloaveolar structure of the gland. After parturition, changes in the hormonal environment lead to production and secretion of milk. Proliferation and differentiation of mammary epithelium can be induced in culture systems. Insulin and epidermal growth factor (EGF) stimulate mammary cell proliferation in vitro. EGF is required for the optimal growth of the mammary gland during pregnancy. EGF also appears to play an important role in mammary tumorigenesis in certain mouse strains. Production of milk proteins can be induced in vitro by the synergistic interactions of prolactin, insulin, and glucocorticoids and is inhibited by EGF and progesterone. Complete or partial sequencing of several milk protein genes and comparative analysis have led to identification of a sequence of high homology and conservation in the 5 'flanking region that is likely to be involved in the regulation of milk protein gene expression.

show abstract

Spectrophotometry in the Far Ultraviolet

Cited by 112 publications

References 3 publications

Linoleic acid, but not cortisol, stimulates accumulation of casein by mouse mammary epithelial cells in serum-free collagen gel culture.

Linoleic acid, but not cortisol, stimulates accumulation of casein by mouse mammary epithelial cells in serum-free collagen gel culture.

Regulation of Functional Cytodifferentiation and Histogenesis in Mammary Epithelial Cells: Role of the Extracellular Matrix

Growth Control and Differentiation in Mammary Epithelial Cells

Contact Info

Product

Resources

About