Correlation of plasma progesterone concentrations to ovarian H-type lipase activity during pseudopregnancy in the rat

Gåfvels, Mats; Bengtsson‐Olivecrona, Gunilla; Olivecrona, Thomas

doi:10.1530/jrf.0.0860589

Cited by 9 publications

(9 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ovaries and adrenals of rats and humans have been shown to contain a lipase activity (liver-or l-type lipase) similar to hepatic lipase (HL) normally present in liver sinusoids [1][2][3][4][5]. Whereas the liver enzyme plays a role in the uptake of circulating lipoproteins and its components, the l-type lipase in the steroidogenic organs is suggested to mediate the delivery of high-density lipoprotein cholesterol required for hormone synthesis [6].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hepatic lipase gene expression is transiently induced by gonadotropic hormones in rat ovaries

Bruggen¹,

Verhoeven²,

Heuveling³

et al. 1997

Molecular and Cellular Endocrinology

View full text Add to dashboard Cite

Hepatic lipase (HL) gene expression was studied in rat ovaries. A transcript lacking exons 1 and 2 could be detected by reverse transcription-polymerase chain reaction (RT-PCR) in the ovaries of mature cyclic females and of immature rats treated with pregnant mare serum followed by human chorionic gonadotropin (hCG) to induce superovulation. By competitive RT-PCR the HL transcript was quantified. Low levels of HL mRNA were detected in ovaries of mature cyclic females and of immature rats. During superovulation HL mRNA was several fold higher than in mature cyclic rats and transiently increased to a maximum at 2 days after hCG treatment. Pulse-labelling of ovarian cells and ovarian slices with [ 35 S]methionine followed by immunoprecipitation with polyclonal anti-HL IgGs showed de novo synthesis of a 47 kDa HL-related protein. Expression of the protein was transiently induced by gonadotropins with a peak at 2 days after hCG treatment. Induction of liver-type lipase activity occurred only after HL mRNA and synthesis of the HL-related protein had returned to pre-stimulatory levels. We conclude that in rat ovaries the HL gene is expressed into a variant mRNA and a 47 kDa protein. The expression of the HL gene in ovaries is inducible and precedes the expression of the mature, enzymatically active liver-type lipase.

show abstract

Section: Introductionmentioning

confidence: 99%

“…The l-type lipase activity in the ovaries varies during the oestrous cycle and lactation in parallel with progesterone and 20h-hydroxyprogesterone output [2,7,8].…”

Section: Introductionmentioning

confidence: 99%

Hepatic lipase gene expression is transiently induced by gonadotropic hormones in rat ovaries

Bruggen¹,

Verhoeven²,

Heuveling³

et al. 1997

Molecular and Cellular Endocrinology

View full text Add to dashboard Cite

show abstract

“…These assays demonstrated that the human HL promoter region is active in these cells, and that promoter activity in these cells is enhanced by 8-Br-cAMP, which mimics the effect of ACTH. An increased HL expression in these organs may be important to maintain the high steroid production, possibly by accelerating the SR-BI mediated uptake of HDL cholesterol (6,14,16,17). The presence of full-length HL mRNA in these activated adrenals strongly suggests that at least part of the adrenal HL activity originates from local synthesis.…”

Section: Discussionmentioning

confidence: 99%

“…3.1.1.34) activity is present in the adrenal cortex of several mammals including man (1)(2)(3)(4), as well as in rat ovaries (5)(6)(7)(8). The HL activity from rat, mouse, and human adrenals is indistinguishable from HL in liver and post-heparin plasma (2,5,(8)(9)(10).…”

Section: Introductionmentioning

confidence: 99%

“…Notably, the enzyme facilitates the cellular uptake of cholesterol carried in high-density lipoprotein (HDL) (12,13). Several lines of evidence indicate that the HL activity in the steroidogenic organs is also involved in the uptake of cholesterol necessary for steroid production (6,8,14,15), probably by accelerating the SR-BI mediated uptake of HDL cholesterol (16,17).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cloning, expression, and promoter analysis of hepatic lipase derived from human hyperplastic adrenals

Botma

Heuveling

Lamers

et al. 2007

Cell Biochem Biophys

View full text Add to dashboard Cite

Human adrenals contain hepatic lipase (HL) activity, which is thought to facilitate the uptake of plasma cholesterol used in steroidogenesis. We show here that full-length HL mRNA is expressed in hyperplastic adrenals of patients with Cushing's disease. In addition, a splice variant that lacks exon-3 was detected in the human adrenals and hepatoma (HepG2) cells, but not in liver. In CAT-reporter assays using human NCI-H295R adrenocortical cells, the HL(-685/+13) promoter region was transcriptionally active, and its activity was enhanced twofold by cAMP. In rat adrenals, the HL gene is exclusively transcribed from an alternative promoter within intron-2, resulting in a variant mRNA that lacks exons 1 and 2. By reverse-transcription PCR, we found no evidence for expression of such a variant mRNA in human adrenals, liver, or HepG2 cells. The presence of both fulllength mRNA and enzyme activity in human adrenals suggests that part of the HL activity is locally synthesized.

show abstract

Heterogeneity among ovarian blood vessels: Endogenous hepatic lipase is concentrated in blood vessels of rat corpora lutea

Hixenbaugh

Paavola

1991

Anat. Rec.

View full text Add to dashboard Cite

We used indirect immunofluorescence and immunogold light microscopy to examine the distribution of hepatic lipase, an enzyme involved in lipoprotein metabolism, in ovaries of gonadotropin-treated immature rats. Antibodies utilized were rabbit anti-rat hepatic lipase IgG, anti-rat von Willebrand factor (VWF, an endothelial cell marker), and goat anti-rabbit IgG conjugated to gold particles or rhodamine. Immunoreagents were applied to fresh frozen sections of unfixed ovary or liver (positive control) or were delivered to ovaries by vascular perfusion before fixation in situ and silver-enhancement of sections. Appropriate controls verified that the immunolocalizations were specific. Immunofluorescence implied that luteal but not stromal blood vessels of ovaries were positive for hepatic lipase, whereas luteal and stromal blood vessels bore VWF. The improved morphology gained by perfusing ovaries with antibodies allowed precise localization of the enzyme. Hepatic lipase was concentrated within thin-walled vessels of corpora lutea but not those of stroma in ovaries at the time of peak steroidogenic activity. Quantification of hepatic lipase-labeled vessels in stromal and luteal compartments confirmed our visual impression. Many images suggested that stromal vessels lacking hepatic lipase gained this enzyme upon contact with luteal tissue. Perfusion of ovaries with cationized ferritin labeled all ovarian vessels equally well, ruling out the possibility that the observed distribution of hepatic lipase was artifactual. These findings demonstrate that ovarian blood vessels are heterogeneous for hepatic lipase. Moreover, they imply that luteal tissue, perhaps luteal cells, may influence expression of hepatic lipase binding sites by endothelial cells.

show abstract

Correlation of plasma progesterone concentrations to ovarian H-type lipase activity during pseudopregnancy in the rat

Cited by 9 publications

References 27 publications

Hepatic lipase gene expression is transiently induced by gonadotropic hormones in rat ovaries

Hepatic lipase gene expression is transiently induced by gonadotropic hormones in rat ovaries

Cloning, expression, and promoter analysis of hepatic lipase derived from human hyperplastic adrenals

Heterogeneity among ovarian blood vessels: Endogenous hepatic lipase is concentrated in blood vessels of rat corpora lutea

Contact Info

Product

Resources

About