| 1. |
- Ling, Charlotte, et al.
(författare)
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Identification of Functional Prolactin (PRL) Receptor Gene Expression: PRL Inhibits Lipoprotein Lipase Activity in Human White Adipose Tissue
- 2003
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Ingår i: The Journal of Clinical Endocrinology & Metabolism. - : The Endocrine Society. - 0013-7227 .- 1945-7197 .- 0021-972X. ; 88:4
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Tidskriftsartikel (refereegranskat)abstract
- During lactation serum levels of prolactin (PRL) are elevated, and the activity of lipoprotein lipase (LPL) is decreased in the adipose tissue and increased in the mammary gland. However, PRL has been suggested to affect the adipose tissue in an indirect fashion during lactation. In the present study, we demonstrated expression of four PRL receptor (PRLR)mRNA isoforms (L, I, S1a, and S1b) in human sc abdominal adipose tissue and breast adipose tissue using RT-PCR/Southern blot analysis. In addition, L-PRLR [relative molecular mass (Mr) 90,000] and I-PRLR (Mr 50,000) protein expression was detected in human sc abdominal adipose tissue and breast adipose tissue using immunoblot analysis. Two additional protein bands with the molecular weight Mr 40–35,000 were also detected. The direct effect of PRL on the regulation of LPL activity in human abdominal adipose tissue cultured in vitro was investigated. PRL (500 ng/ml) reduced the LPL activity in human adipose tissue to 31 +/- 7.7%, compared with control.GH (100 ng/ml) also reduced the LPL activity, to 45 +/- 8.6%, compared with control. In agreement with previous studies, cortisol increased the LPL activity and GH inhibited cortisolinduced LPL activity. Furthermore, we found that PRL also inhibited the cortisol-induced LPL activity. Taken together, these results demonstrate a direct effect of PRL, via functional PRLRs, in reducing the LPL activity in human adipose tissue, and these results suggest that LPL might also be regulated in this fashion during lactation.
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| 2. |
- Nilsson, Louise, 1975, et al.
(författare)
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A common variant near the PRL gene is associated with increased adiposity in males
- 2011
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Ingår i: Molecular Genetics and Metabolism. - : Elsevier BV. - 1096-7192. ; 102:1, s. 78-81
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Tidskriftsartikel (refereegranskat)abstract
- A common variant (rs4712652) adjacent to the prolactin gene was recently associated with obesity using a genome-wide association study. The aim of this study was to replicate the association between rs4712652 and obesity and further examine if rs4712652 is associated with fat percentage and adiponectin levels in a population based Scandinavian cohort. rs4712652 was genotyped in 4879 participants (mean BMI 26.5 +/- 4.5 kg/m(2)) from the population-based PPP-Botnia Study and related to BMI, fat percentage and adiponectin levels. We found that the risk A allele of rs4712652 is associated with increased BMI and fat percentage in males (P=0.0047 and P=0.025, respectively), but not in females (P = 0.98, P=0.45). Male A allele carriers have a higher risk of being overweight with an OR of 1.16 (P=0.025). While there was a significant negative correlation between adiponectin levels and fat percentage (r = -036; P=0.039) in male carriers of the protective GG genotype, this correlation was lost in male carriers of the risk rs4712652 A allele (P=0.33). Thus, the common SNP rs4712652 near the PRL gene seems to affect body fat and adiposity in a sex-specific fashion. It remains to be shown whether this is mediated by different prolactin concentrations or differences in tissue sensitivity to prolactin. (C) 2010 Elsevier Inc. All rights reserved.
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| 3. |
- Nilsson, Louise, 1975, et al.
(författare)
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Prolactin and growth hormone regulate adiponectin secretion and receptor expression in adipose tissue
- 2005
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Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 1090-2104 .- 0006-291X. ; 331
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Tidskriftsartikel (refereegranskat)abstract
- Adiponectin is a hormone secreted from adipose tissue, and serum levels are decreased with obesity and insulin resistance. Because prolactin (PRL) and growth hormone (GH) can affect insulin sensitivity, we investigated the effects of these hormones on the regulation of adiponectin in human adipose tissue in vitro and in rodents in vivo. Adiponectin secretion was significantly suppressed by PRL and GH in in vitro cultured human adipose tissue. Furthermore, PRL increased adiponectin receptor 1 (AdipoR1) mRNA expression and GH decreased AdipoR2 expression in the cultured human adipose tissue. In transgenic mice expressing GH, and female mice expressing PRL, serum levels of adiponectin were decreased. In contrast, GH receptor deficient mice had elevated adiponectin levels, while PRL receptor deficient mice were unaffected. In conclusion, we demonstrate gene expression of AdipoR1 and AdipoR2 in human adipose tissue for the first time, and show that these are differentially regulated by PRL and GH. Both PRL and GH reduced adiponectin secretion in human adipose tissue in vitro and in mice in vivo. Decreased serum adiponectin levels have been associated with insulin resistance, and our data in human tissue and in transgenic mice suggest a role for adiponectin in PRL and GH induced insulin resistance.
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| 4. |
- Nilsson, Louise, 1975, et al.
(författare)
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Prolactin suppresses malonyl-CoA concentration in human adipose tissue.
- 2009
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Ingår i: Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et métabolisme. - : Georg Thieme Verlag KG. - 1439-4286 .- 0018-5043. ; 41:10, s. 747-51
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Tidskriftsartikel (refereegranskat)abstract
- Prolactin is best known for its involvement in lactation, where it regulates mechanisms that supply nutrients for milk production. In individuals with pathological hyperprolactinemia, glucose and fat homeostasis have been reported to be negatively influenced. It is not previously known, however, whether prolactin regulates lipogenesis in human adipose tissue. The aim of this study was to investigate the effect of prolactin on lipogenesis in human adipose tissue in vitro. Prolactin decreased the concentration of malonyl-CoA, the product of the first committed step in lipogenesis, to 77+/-6% compared to control 100+/-5% (p=0.022) in cultured human adipose tissue. In addition, prolactin was found to decrease glucose transporter 4 ( GLUT4) mRNA expression, which may cause decreased glucose uptake. In conclusion, we propose that prolactin decreases lipogenesis in human adipose tissue as a consequence of suppressed malonyl-CoA concentration in parallel with decreased GLUT-4 expression. In the lactating woman, this regulation in adipose tissue may enhance the provision of nutrients for the infant instead of nutrients being stored in adipose tissue. In hyperprolactinemic individuals, a suppressed lipogenesis could contribute to an insulin resistant state with consequences for the health.
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| 5. |
- Shao, Linus Ruijin, 1964, et al.
(författare)
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Developmental and hormonal regulation of progesterone receptor A-form expression in female mouse lung in vivo: interaction with glucocorticoid receptors
- 2006
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Ingår i: The Journal of endocrinology. - : Bioscientifica. - 0022-0795 .- 1479-6805. ; 190:3, s. 857-70
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Tidskriftsartikel (refereegranskat)abstract
- Progesterone (P(4)) regulates many aspects of physiological functions via two nuclear P(4) receptors (PR), PRA and PRB, which are members of a structurally related nuclear hormone receptor superfamily that includes glucocorticoid receptors (GR). The regulation and cellular distribution of PR protein isoforms have been extensively studied in reproductive tissues, but this is not the case in the lung. In the present study, reverse transcriptase (RT)-PCR, Western blotting, and immunolocalization supported the presence of PRA in the lung of female mice, with PRA protein levels significantly increased between postnatal day 7 and 12, declined at postnatal day 26, and minimal in adults when compared to postnatal day 2. The peak was temporally related to postnatal lung maturation in rodents. Immunoreactivity for PR was detected in the alveolar and bronchial epithelia. We then extended this study to examine, for the first time, the regulation of PRA protein expression in female mouse lung in vivo. Neither the increase in endogenous P(4) nor treatment with exogenous P(4) regulated PRA protein expression in female mouse lung. However, treatment of mice with the GR/PR antagonist RU 486, but not Org 31710 (a specific PR antagonist), significantly increased PRA protein expression in parallel to a decrease in GR protein expression. In addition, treatment with the synthetic glucocorticoid dexamethasone led to a decrease in PRA protein expression independent of endogenous P(4) levels. Furthermore, immunoprecipitation followed by Western blot analysis revealed that, under in vivo conditions, PRA physically interacted with GR in mouse lung. Confocal laser microscopy revealed that PRA and GR co-localized in the nuclei of alveolar epithelia cells, whereas nuclear PR and cytoplasmic GR were detected in bronchial epithelium. Taken together, our observations suggest that PRA may be an important physiological factor involved in postnatal lung development and that the regulation of PRA protein expression is not dependent on P(4), but rather on functional glucocorticoid/GR signaling mediated by protein-protein interaction in the mouse lung.
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| 6. |
- Shao, Linus Ruijin, 1964, et al.
(författare)
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Differences in prolactin receptor (PRLR) in mouse and human fallopian tubes: Evidence for multiple regulatory mechanisms controlling PRLR isoform expression in mice
- 2008
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Ingår i: Biology of Reproduction. - : Oxford University Press (OUP). - 1529-7268 .- 0006-3363. ; 79:4, s. 748-757
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Tidskriftsartikel (refereegranskat)abstract
- The anterior pituitary-derived hormone prolactin (PRL) signals through the PRL receptor (PRLR) and is important for female reproductive function in mammals. In contrast to the extensive studies of PRLR expression and regulation in human and mouse ovary and uterus, the mechanisms controlling the regulation of PRLR isoform expression in the fallopian tube are poorly understood. Because dynamic interaction of hormonal signaling in gonadal tissue and the pituitary or in gonadal tissues themselves in mammals suggests endocrine or paracrine regulation of PRLR expression, we questioned whether differential regulation of PRLR isoforms by PRL ovarian-derived estrogen (E-2) and progesterone (P-4) exists in the fallopian tube and pituitary of prepubertal female mice. Western blot analysis showed distinct molecular separation of PRLR isoforms in mouse and human fallopian tubes, and cellular localization was found in mouse and human tubal epithelia but not in mouse tubal smooth muscle cells. These data support the concept of an isoform- and cell type-specific expression of PRLR in human and mouse fallopian tubes. Moreover, expression of the long form of PRLR decreased after PRL treatment and increased after blockage of endogenous PRL secretion by bromocriptine (an inhibitor of PRL secretion) in a time-dependent manner in mouse fallopian tube. The opposite regulation was observed in the pituitary. Treatment with exogenous E-2 or P-4 led to changes in PRLR expression in the fallopian tube Similar to those of PRL treatment. However, E-2 and P-4 did not affect PRLR expression in the pituitary. Estrogen had no effect on the long form of PRLR expression, whereas P-4 regulated the long form of PRLR in the fallopian tube, as did PRL. Taken together, the data from our comparative study provide evidence that PRLR can be regulated by an interplay of two different mechanisms, PRL or ovarian steroid hormones independently or in combination in a tissue-specific manner. Furthermore, we found that ovarian steroid hormones selectively suppress the expression of PRLR isoforms in mouse fallopian tubes. These findings may contribute to our understanding of the mechanisms controlling PRLR isoform expression in the fallopian tube (in addition to ovary and uterus), with implications for female reproduction.
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