Original article Messenger RNAs encoding lipoprotein lipase, fatty acid synthase and hormone-sensitive lipase in the adipose tissue of underfed-refed ewes and cows Muriel Bonnet a Yannick Faulconnier a Jeanne Fléchet a Jean-François Hocquette Christine Leroux c Dominique Langin Patrice Martin Yves Chilliard a Laboratoire sous-nutrition des ruminants, Inra, Theix, 63122 Saint-Genès-Champanelle, France b Laboratoire croissance et métabolismes des herbivores, Inra, 63122 Saint-Genès-Champanelle, France C Laboratoire de génétique biochimique et de cytogénétique, Inra, 78352 Jouy-en-Josas cedex, France d Institut Louis Bugnard, Hôpital Rangueil, Inserm U317, 31403 Toulouse cedex 4, France (Received 6 October 1997; accepted 23 March 1998) Abstract - The mechanisms involved in the nutritional regulation of genes encoding lipogenic (lipoprotein lipase (LPL) and fatty acid synthase (FAS)) and lipolytic (hormone-sensitive lipase (HSL)) enzymes were investigated by comparing the levels of the corresponding mRNAs in the adipose tissue (AT) of underfed or underfed-refed ewes and cows. Refeeding sharply increased LPL and FAS activities (19-25- and 6-8-fold, respectively) and moderately increased (2-4 fold) the activities of glucose-6-phosphate dehydrogenase (G6PDH), malic enzyme (ME) and glyce- rol-3-phosphate dehydrogenase (G3PDH). Northern blot analysis revealed three LPL transcripts and a single FAS transcript in cow and ewe AT. A single HSL mRNA was detected in cow AT and two transcripts in ewe AT. Refeeding sharply increased LPL and FAS mRNA levels, while restriction slightly increased (cows) or had no effect (ewes) on the HSL mRNA levels. This sug- gests that nutritional factors regulate sharply the expression of LPL and FAS genes by pretrans- lational mechanisms, but less clearly that of HSL gene. @ Inra/Elsevier, Paris ruminants / adipose tissue / enzyme activities / mRNAs / refeeding * Correspondence and reprints E-mail: chilliar!clermont.inra.fr