Apoprotein E-rich high density lipoproteins inhibit ovarian XXXX synthesis.

@entity1 @entity1871 @entity134 @entity342 @entity35 @entity3800
The influence of high density lipoproteins (HDL) on luteinizing hormone-stimulated @entity35 ovarian theca/interstitial cell steroidogenesis was studied. Without HDL the cells produced primarily @entity3800 from @entity1871 precursors. In the presence of @entity35 or @entity1 HDL @entity134 output increased 3-5-fold, but the type of @entity134 produced was dependent on the source of the HDL. @entity1 HDL nonselectively amplified luteinizing hormone-stimulated @entity134 production, whereas @entity35 HDL promoted progestin production without a concomitant increase in @entity342 output. Comparisons of the activities of apoprotein E-rich HDL (e.g. HDL from intact mature @entity35 ) with apoprotein E-poor HDL (e.g. @entity1 HDL or @entity35 HDL from hypophysectomized immature @entity35 ) suggested that apoprotein E was responsible for the inhibition of @entity342 production. Furthermore, the inhibitory activity of @entity35 HDL was abolished by depleting apoprotein E-containing lipoproteins with heparin affinity chromatography. Direct evidence that apoprotein E was the inhibitory constituent of @entity35 HDL was obtained by showing that isolated lipid-free @entity35 apoprotein E inhibited @entity342 production, whereas isolated @entity35 apoproteins A-I and A-IV did not. The possible paracrine function of apoprotein E in ovarian follicular maturation of the ovary is discussed.
