Milk accumulation triggers apoptosis of mammary epithelial cells.
Continuous milk production is a consequence of a complex interplay of lactogenic hormones and it depends on the suckling stimulus during lactation. Involution is associated with a massive engorgement of the gland with milk followed by apoptosis of secretory epithelial cells and a restructing of the gland. Sealing of a single gland during lactation is sufficient to induce an initial engorgement and a subsequent collapse of alveolar structures and massive epithelial cell death while the other glands of the same animal remain morphologically and functionally in a lactating state. Many markers of involution such as sulfated glycoprotein-2, protein kinase A, transcription factor AP-1 and most notably stromelysin are induced in sealed glands. These findings suggest a cell death pathway which is independent of the systemic levels of lactogenic hormones but which is triggered by an accumulation of apoptosis-inducing factors in the milk, in the lobulo-alveolar structures or by a physical distortion of secretory epithelial cells generated by the engorgement.
Marti
A
A
Laboratory for Clinical and Experimental Research, University of Bern, Switzerland.
Feng
Z
Z
Altermatt
H J
HJ
Jaggi
R
R
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D001483:Base Sequence; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D053938:DNA Fragmentation; D004848:Epithelium / Q000378:metabolism / Q000502:physiology; D005260:Female; D015870:Gene Expression; D016762:Genes, fos; D016758:Genes, jun; D007774:Lactation / Q000502:physiology; D008321:Mammary Glands, Animal / Q000166:cytology* / Q000502:physiology*; D051379:Mice; D008892:Milk / Q000378:metabolism / Q000502:physiology*; D009838:Oligodeoxyribonucleotides / Q000235:genetics / Q000378:metabolism
D009838:Oligodeoxyribonucleotides; D004247:DNA; D017868:Cyclic AMP-Dependent Protein Kinases