Binding of High-Density Lipoproteins to Luteal Membranes. The Role of Prolactin, Luteinizing Hormone, and Circulating Lipoproteins

Rajkumar, K.; Couture, Roxanne; Murphy, Bruce D.

doi:10.1097/00006254-198510000-00014

Cited by 4 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These lipoproteins were apparently present in the serum supplement of the medium in which cells in this experiment were grown. However, this finding and earlier reports by Rajkumar et al [11,12] do not exclude the role of PRL-R in the mechanism underlying Tc and ECL functions in the porcine ovary. The present preliminary study using Scatchard analysis revealed for the first time in the pig, femtomol levels of PRL-R protein in Tc of medium and large follicles.…”

Section: Identification Of Prl-r By Binding Assayscontrasting

confidence: 87%

Prolactin Binding Analysis and Immunohistochemical Localization of Prolactin Receptor in Porcine Ovarian Cells.

et al. 2001

View full text Add to dashboard Cite

Abstract.In the present study we searched for prolactin receptor (PRL-R) in porcine ovarian theca tissue (Tc) of small, medium and large follicles, as well as in early corpus luteum (ECL). The objectives of this investigation were: 1) comparison of the direct effect of PRL action on progesterone (P4) and estradiol (E2) secretion from Tc and ECL cells in culture with adequate effects caused by luteinizing hormone (LH). 2) detection of the presence and distribution of PRL-R in thecal tissue of porcine follicles and in ECL. Tissues were cultured as monolayers either in control M199 medium with calf serum or in medium either with PRL (100 ng/ml) or with LH (100 ng/ml). After 2 days in vitro cultured media were assayed for steroid concentrations by radioimmunoassays.Content and distribution of PRL-R were evaluated by Scatchard analysis and by an immunohistochemical assay. Separated theca layers as well as fragments of ECL were excised on dry ice, homogenized, and incubated with [1251]-PRL. PRL stimulated P4 secretion from Tc 10-fold versus controls. LH stimulated P4 secretion only 2.5-fold. E2 secretion was stimulated by PRL 2.7-fold and by LH 2.4-fold.LH enhanced P4 secretion from ECL cells by 18% while PRL increased P4 secretion by as much as 73%. Femtomol amounts of PRL-R protein were detected in theca tissues of medium and large follicles and also in ECL, which was in accordance with immunohistochemical results. The results showed for the first time the presence of PRL-R in porcine Tc and ECL.

show abstract

Section: Identification Of Prl-r By Binding Assayscontrasting

confidence: 87%

Prolactin Binding Analysis and Immunohistochemical Localization of Prolactin Receptor in Porcine Ovarian Cells.

et al. 2001

View full text Add to dashboard Cite

show abstract

“…Cholesterol from the various sources can then be utilized for steroid synthesis or can be incorporated into cholesterol esters by acyl CoA cholesterol acyltransferase (ACAT) and stored as lipid droplets (reviewed in [10]). As luteal progesterone secretion increases during the luteal phase of the reproductive cycle, lipoprotein binding sites increase on luteal cells [11,12].…”

Section: Introductionmentioning

confidence: 99%

Luteal Function: The Estrous Cycle and Early Pregnancy

Niswender

Juengel

McGuire

et al. 1994

Biology of Reproduction

150

View full text Add to dashboard Cite

A number of morphological and biochemical changes occur as the cells of the recently ovulated follicle luteinize and develop into a functional CL. There are two distinct steroidogenic luteal cell types that appear to differentiate from thecal and granulosal cells in the follicle. The control of progesterone secretion is quite different in the two cell types. Prostaglandin F2 alpha (PGF2 alpha) is the primary luteolytic hormone in most mammals. PGF2 alpha appears to exert its antisteroidogenic actions via activation of the protein kinase C system, while its cytotoxic effects appear to be mediated via a dramatic increase in intracellular levels of free calcium. The mechanisms involved in maternal recognition of pregnancy are very diverse between species and may involve direct luteotropic stimulation of the CL, reduced uterine secretion of PGF2 alpha, and/or inhibition of actions of PGF2 alpha at the level of the CL.

show abstract

“…The rat corpus luteum has one of the highest known rates of steroid hormone production. Luteinized tissue from rats binds highdensity lipoprotein (HDL) particles (Christie et al, 1981;Rajkumar et al, 1985). Treatment with 4-aminopyrazolo (3,4,-d)pyrimidine, a drug known to depress hepatic secretion of lipoprotein cholesterol without altering luteal morphology, decreased luteal cholesterol concentration and progesterone production (Andersen & Dietschy, 1978;Christie et al, 1979).…”

Section: Introductionmentioning

confidence: 99%

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

Gåfvels¹,

Bengtsson‐Olivecrona²,

Olivecrona³

1989

Reproduction

View full text Add to dashboard Cite

Conditions for extraction and assay of hepatic type (H-type) lipase from rat ovaries were studied. An alkaline buffer with protease inhibitors and detergents gave the most efficient extraction. The specificity of the assays was ascertained using antiserum to H-type lipase from heparin perfusates of rat livers. H-type lipase activity was determined in ovarian compartments during pseudopregnancy (1-13 days) as well as during the ensuing period of luteal regression (Day 17). The activity was low in the luteal compartment immediately after ovulation, increased 6-fold to a maximum between Day 5 and Day 8 and then decreased again. This is similar to previously known changes in blood flow. There was a significant correlation between luteal H-type lipase activity and plasma progesterone regardless of luteal age. In contrast, neither the activity in the remainder of the ovary nor the activity in plasma changed during the luteal phase or correlated to plasma progesterone. Injection of heparin at the height of the luteal cycle (Day 8) caused a pronounced decrease in luteal lipase and in plasma progesterone. These studies suggest that the H-type lipase activity has an important role in luteal steroidogenesis, probably to facilitate uptake of cholesterol from lipoproteins.

show abstract

Binding of High-Density Lipoproteins to Luteal Membranes. The Role of Prolactin, Luteinizing Hormone, and Circulating Lipoproteins

Cited by 4 publications

References 0 publications

Prolactin Binding Analysis and Immunohistochemical Localization of Prolactin Receptor in Porcine Ovarian Cells.

Prolactin Binding Analysis and Immunohistochemical Localization of Prolactin Receptor in Porcine Ovarian Cells.

Luteal Function: The Estrous Cycle and Early Pregnancy

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

Contact Info

Product

Resources

About