Related Experiment Video
Updated: Aug 18, 2026

Mouse Mammary Epithelial Cells form Mammospheres During Lactogenic Differentiation
Published on: October 6, 2009
Expression of a calcium-mobilizing parathyroid hormone-like peptide in lactating mammary tissue
1Department of Bone Biology and Osteoporosis Research, Merck Sharp & Dohme Research Laboratories, West Point, PA 19486.
Abstract:
A survey of rat tissues by RNA analysis, aimed at uncovering the physiological function of the parathyroid hormone-like peptide (PTH-LP) associated with hypercalcemia of malignancy, revealed the presence of a 1.5-kilobase messenger RNA encoding this peptide in lactating mammary glands. PTH-LP messenger RNA is expressed in mammary tissue only during lactation; it appears and disappears rapidly (2 to 4 hours) as a function of the sucking stimulus. The identity of this messenger RNA was confirmed by cloning the rat PTH-LP complementary DNA, which predicts a peptide with strong similarity to the human homolog. Moreover, extracts from lactating mammary tissue stimulated parathyroid hormone-dependent adenylate cyclase. These findings suggest that PTH-LP plays a physiological role in lactation, possibly as a hormone for the mobilization or transfer (or both) of calcium to the milk.
Related Concept Videos
Feedback Regulation of Calcium Concentration
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Calmodulin-dependent Signaling
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
Hormones and Bone Tissue
Hormones That Influence Osteoblasts and/or Maintain the Matrix
Several hormones are necessary for controlling bone growth and maintaining the bone matrix. The pituitary gland secretes growth hormone (GH), which, as its name implies, controls bone growth. This happens in several ways: first, it triggers chondrocyte...
Synthesis and Functions of Calcitonin
The exact mechanisms by which calcitonin operates in calcium homeostasis remain elusive, but its significance is evident in several vital...
The Parathyroid Glands
Oxyphil cells, whose functions remain elusive, emerge during late puberty, adding a layer of complexity to the parathyroid gland's intricacies. In contrast, principal parathyroid cells undertake a vital role by producing...
The Mammary Glands
Each breast features a pigmented projection known as the nipple, through which milk emerges via closely spaced openings of ducts, referred to as lactiferous ducts. Surrounding the nipple is a circular pigmented area of skin named the areola, which appears rough due to...

