Expression of a calcium-mobilizing parathyroid hormone-like peptide in lactating mammary tissue.
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.
Thiede
M A
MA
Department of Bone Biology and Osteoporosis Research, Merck Sharp & Dohme Research Laboratories, West Point, PA 19486.
Rodan
G A
GA
D000262:Adenylyl Cyclases / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism*; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007774:Lactation / Q000378:metabolism*; D008321:Mammary Glands, Animal / Q000378:metabolism*; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics* / Q000502:physiology; D044162:Parathyroid Hormone-Related Protein; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D012689:Sequence Homology, Nucleic Acid; D014018:Tissue Distribution
D009363:Neoplasm Proteins; C470121:PTHLH protein, human; D044162:Parathyroid Hormone-Related Protein; D012333:RNA, Messenger; D004247:DNA; D000262:Adenylyl Cyclases; D002118:Calcium