Prolactin's effects on lipoprotein lipase (LPL) activity and on LPL mRNA levels in cultured mouse mammary gland explants

Proc Soc Exp Biol Med. 1997 Feb;214(2):161-6. doi: 10.3181/00379727-214-44083.

Abstract

The in vitro effects of prolactin (PRL) on lipoprotein lipase (LPL) activity and on LPL mRNA levels were studied in cultured mammary tissues derived from mid-pregnant mice. Mouse mammary gland tissues were initially incubated for 24 hr in M199 media containing 1 microg/ml insulin and 10(-7) M cortisol. A subsequent treatment of the tissues with 1 microg/ml PRL caused a 76% increase in heparin-releasable LPL (hrLPL) activity after 24 hr. A significant increase in LPL activity was detected 16 hr after PRL addition, but not at earlier times. PRL at 100 ng/ml elicited a maximum stimulation of LPL activity. When Northern hybridization techniques were employed, PRL was also found to increase the tissue content of LPL mRNA; this effect was initially detected after a 6-hr PRL treatment employing PRL concentrations of 50 ng/ml and above. Specificity studies revealed that only lactogenic hormones stimulated LPL activity and LPL mRNA accumulation in cultured mammary tissues. PRL also expressed a small (25% increase), but significant, effect on ATP citrate-lyase activity in mammary tissues cultured for more than 6 hr with the hormone.

MeSH terms

  • ATP Citrate (pro-S)-Lyase / metabolism
  • Animals
  • Blotting, Northern
  • Dose-Response Relationship, Drug
  • Female
  • Lipoprotein Lipase / genetics
  • Lipoprotein Lipase / metabolism*
  • Mammary Glands, Animal / drug effects
  • Mammary Glands, Animal / enzymology*
  • Mice
  • Organ Culture Techniques
  • Pregnancy
  • Prolactin / pharmacology*
  • RNA / isolation & purification
  • RNA, Messenger / metabolism*

Substances

  • RNA, Messenger
  • RNA
  • Prolactin
  • ATP Citrate (pro-S)-Lyase
  • Lipoprotein Lipase