Sequence of prolactin effects on phospholipid synthesis in mouse mammary gland explants.
In cultured mouse mammary gland explants derived from 12-14 day pregnant mice, the effect of prolactin (PRL) on the rate of incorporation of several precursors into neutral lipids and phospholipids was determined. Employing [14C]-acetate as a substrate, PRL stimulates its incorporation into a) neutral lipids by 4-6 hours, b) phosphatidyl choline (PC) and phosphatidyl inositol-phosphatidyl serine (PI-PS) by 1-2 hours, and c) phosphatidyl ethanolamine (PE) by 2-4 hours. Using [3H]-glycerol as a substrate, the temporal response to PRL for its incorporation into the neutral lipids was the same as that for [14C]-acetate, however, PRL did not enhance the rate of [3H]-glycerol incorporation into the phospholipids at any time through 16 hours. PRL similarly had no effect on the rates of [3H]-choline, [3H]-serine, [3H]-ethanolamine, or [32P]O4 incorporation into the phospholipids at hormone exposure periods of 8 hours or more. And finally, PRL had no effect on the rates of [3H]-arachidonate or [14C]-linoleate incorporation into neutral lipids or phospholipids at culture periods up to 18 hours. These data suggest that the early effect of PRL on [14C]-acetate incorporation into the phospholipids is due to either the insertion of newly synthesized fatty acids and/or the extension of fatty acids contained in the phospholipids.
Rillema
J A
JA
Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan.
Waters
S B
SB
Whale
M A
MA
D000085:Acetates / Q000378:metabolism; D000818:Animals; D046508:Culture Techniques; D004983:Ethanolamines / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism; D050356:Lipid Metabolism; D008321:Mammary Glands, Animal / Q000378:metabolism*; D051379:Mice; D010713:Phosphatidylcholines / Q000378:metabolism; D010743:Phospholipids / Q000096:biosynthesis*; D011247:Pregnancy; D011388:Prolactin / Q000494:pharmacology*; D013109:Sphingomyelins / Q000378:metabolism
D000085:Acetates; D004983:Ethanolamines; D010713:Phosphatidylcholines; D010743:Phospholipids; D013109:Sphingomyelins; D011388:Prolactin; D005947:Glucose; D005990:Glycerol