Ultrastructural changes in porcine mammary tissue during lactogenesis

R. S. Kensinger, Robert J Collier, F. W. Bazer

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Ultrastructural changes occurring in porcine mammary tissue were characterised between Day 90 of pregnancy and Day 4 of lactation. Porcine mammary tissue on Day 90 of pregnancy was composed of alveoli which contained negligible to moderate amounts of secretion. Epithelial cells of these alveoli were relatively undifferentiated. The appearance and distribution of cellular organelles suggested that mammary epithelial differentiation had been initiated by Day 105 of pregnancy in the pig. A further increase in intracellular lipid droplets and granular endoplasmic reticulum suggested that differentiation had progressed by Day 112. On the day of parturition, secretions within the alveolar lumina assumed the appearance of normal milk (as opposed to colostrum) and the epithelia displayed a distinct cellular polarity characteristic of lactating mammary tissue. By Day 4 of lactation, differentiation of epithelial cells appeared to be complete, with dilated cisternae of the granular endoplasmic reticulum and with numerous secretory vesicles. Elongated microvilli were present and numerous cells contained lipid droplets which were being extruded into the lumina. Data from this and previous studies indicate that lactogenesis in the pig occurs in two stages. Stage 1 occurs between Days 90 and 105 of pregnancy, and Stage 2 between Day 112 of pregnancy and early lactation when the predominant feature is active milk secretion.

Original languageEnglish (US)
Pages (from-to)49-59
Number of pages11
JournalJournal of Anatomy
VolumeVOL. 145
StatePublished - 1986
Externally publishedYes

Fingerprint

milk synthesis
pregnancy
breasts
Breast
Swine
lactation
Pregnancy
swine
Lactation
secretion
Rough Endoplasmic Reticulum
pig
endoplasmic reticulum
milk
droplets
droplet
Milk
epithelial cells
lipid
Epithelial Cells

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Anatomy

Cite this

Ultrastructural changes in porcine mammary tissue during lactogenesis. / Kensinger, R. S.; Collier, Robert J; Bazer, F. W.

In: Journal of Anatomy, Vol. VOL. 145, 1986, p. 49-59.

Research output: Contribution to journalArticle

Kensinger, R. S. ; Collier, Robert J ; Bazer, F. W. / Ultrastructural changes in porcine mammary tissue during lactogenesis. In: Journal of Anatomy. 1986 ; Vol. VOL. 145. pp. 49-59.
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