Horm Metab Res 2003; 35(4): 243-250
DOI: 10.1055/s-2003-39481
Original Clinical
© Georg Thieme Verlag Stuttgart · New York

Growth Hormone-Mediated Breakdown of Body Fat: Effects of GH on Lipases in Adipose Tissue and Skeletal Muscle of Old Rats Fed Different Diets

T.  Johansen 1, 3 , B.  Richelsen 2 , H.  S.  Hansen 3 , N.  Din 4 , K.  Malmlöf 1
  • 1 Dept. of Pharmacology 3, Novo Nordisk, Malov, Denmark
  • 2 Aarhus County Hospital, Aarhus, Denmark
  • 3 The Royal Danish School of Pharmacy, Dept. of Pharmacology, Copenhagen, Denmark
  • 4 Novo Nordisk, Dept. of Transcription Biology, Bagsvaerd, Denmark.
Further Information

Publication History

Received 4 October 2002

Accepted after Revision 9 December 2002

Publication Date:
02 June 2003 (online)

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Abstract

Lipid storage and breakdown is mainly controlled by lipoprotein lipase and hormone-sensitive lipase. The aim of this work was to elucidate whether growth hormone mediated loss of adipose tissue involves a concerted action on tissue lipases, and to what degree such events are modulated by dietary regimen. Twelve-month-old rats fed first a high-fat diet or a low-fat diet for 14 weeks were injected with saline or growth hormone (4 mg/kg/d) for four days or three weeks in different combinations with either high- or low-fat diets. In adipose tissue, growth hormone generally inhibited lipoprotein lipase and also attenuated the inhibiting effect of insulin on hormone-sensitive lipase activity. Growth hormone treatment combined with restricted high-fat feeding reduced the activity of both lipases in adipose tissue and stimulated hormone-sensitive lipase in muscle. Generally, plasma levels of free fatty acids, glycerol and cholesterol were reduced by growth hormone, and in combination with restricted high-fat feeding, triglyceride levels improved too. We conclude that growth hormone inhibits lipid storage in adipose tissue by reducing both lipoprotein lipase activity and insulin's inhibitory action on hormone-sensitive lipase. We also propose that growth hormone's effects on tissue lipases and blood lipids are modulated by dietary regimen.

References

T. Johansen

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