GH) And Its Receptor Research Articles

Association analysis of nucleotide polymorphisms in growth hormone (GH) and its receptor (GHR) with body weight in Californian rabbits

The objective of the present study was to evaluate the influence of the genotypes of two single nucleotide polymorphisms (SNPs) – c.78C>T located in the growth hormone gene (GH) and c.106C>G in the growth hormone receptor gene (GHR) on individual body weight (IBW) during the growing period at 35, 70 and 90 d of age on a total of 107 weaned Californian breed rabbits. The restriction fragments obtained revealed that 74.8% of the rabbits carrying c.78C>T SNP and 52.3% of the rabbits carrying c.106C>G SNP were heterozygous, which indicated a moderate level of genetic diversity in this Californian population. Association analysis based on a single-gene approach revealed that c.78C>T polymorphism in the GH gene had a significant effect (P<0.05) on the weight at 70 and 90 d of age. The highest IBW (2530.4±66.6 g) was observed in rabbits carrying the c.78C>T TT genotype, and detected individuals were significantly affected by the dominance effect. Significant differences were observed between individuals with homozygous c.106C>G CC genotype and those with heterozygous CG genotype. The highest IBW (2462.0±198.3 g) was observed in rabbits carrying the c.106C>G CC genotype and detected individuals were significantly affected by the additive effect. A total of nine combined genotypes of c.78C>T and c.106C>G SNPs was found in the study, of which only four major groups (CT/CC, CC/CG, CT/CG, and CT/GG) were concerned in the diplotype analysis. Significant differences were observed between individuals with CT/CC and CC/CG genotype combinations, and between those with the CC/CG and CT/GG diplotypes. However, the highest IBW at 90 d of age (2447.2±213.8 g) was observed in rabbits carrying the CT/CC genotype combinations. The highest coefficient of determination found for individual body weight at 90 d of age (R2=10.8%) indicated a high effect of genotype combinations. In conclusion, the results obtained suggested that c.78C>T of GH gene and c.106C>G of GHR gene could be useful candidate genes to improve growth performance in Californian rabbits with potential application in rabbit breeding programmes.

Dynamic responses of prolactin, growth hormone and their receptors to hyposmotic acclimation in the olive flounder Paralichthys olivaceus

Prolactin (PRL) and growth hormone (GH) play important roles in regulating salt and water balance through osmoregulatory organs in vertebrates. The aim of this study was to investigate the dynamic changes of GH/PRL hormone gene expressions in the pituitary gland and their receptors in gill and kidney, as well as the plasma osmolality when the olive flounder fish Paralichthys olivaceus were acclimated in freshwater (FW) conditions. After transfer from seawater (SW) to freshwater (FW), the osmolality of FW-adaption fish reached the lowest level at 1d which rose slightly afterwards. However, the hormone gene expression of PRL increased from 2d, reaching its peak at 5d, and then decreased at 14d. At this time, the value was still significantly higher than the control, showing a similar trend to the plasma hormone PRL. In contrast, the pituitary mRNA level of GH significantly decreased at 1d and then returned to normal levels. The mRNA levels of PRL receptor (PRLR) in both gill and kidney displayed a similar trend to the pituitary PRL. We also observed the synchronous expression trend of the renal PRLR with pituitary PRL (5d) and the asynchronous expression peaks between branchial (8d) and renal PRLR (5d). Significant responses of GH and its receptor (GHR) in both gill and kidney during the FW-acclimation were not observed. Nevertheless, the gene expression of GH receptor variant (GHR-V) in both gill and kidney declined at 2d, indicating unknown osmoregulatory functions of GHR-V. Collectively, our results provided more insights of the PRL, GH and their corresponding receptors in modulating osmoregulatory responses, representing an important aspect of FW–acclimation in flounder fish.

Autocrine/paracrine proliferative effect of ovarian GH and IGF-I in chicken granulosa cell cultures

It is known that growth hormone (GH) and its receptor (GHR) are expressed in granulosa cells (GC) and thecal cells during the follicular development in the hen ovary, which suggests GH is involved in autocrine/paracrine actions in the female reproductive system. In this work, we show that the knockdown of local ovarian GH with a specific cGH siRNA in GC cultures significantly decreased both cGH mRNA expression and GH secretion to the media, and also reduced their proliferative rate. Thus, we analyzed the effect of ovarian GH and recombinant chicken GH (rcGH) on the proliferation of pre-hierarchical GCs in primary cultures. Incubation of GCs with either rcGH or conditioned media, containing predominantly a 15-kDa GH isoform, showed that both significantly increased proliferation as determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, proliferating cell nuclear antigen (PCNA) quantification and (3H)-thymidine incorporation (3H-T) assays in a dose response fashion. Both, locally produced GH and rcGH also induced the phosphorylation of Erk1/2 in GC cultures. Furthermore, GH increased IGF-I synthesis and its release into the GC culture incubation media. These results suggest that GH may act through local IGF-I to induce GC proliferation, since IGF-I immunoneutralization completely abolished the GH-induced proliferative effect. These data suggest that GH and IGF-I may play a role as autocrine/paracrine regulators during the follicular development in the hen ovary at the pre-hierarchical stage.

Effects of Double Transgenesis of Somatotrophic Axis (GH/GHR) on Skeletal Muscle Growth of Zebrafish (Danio rerio).

Transgenic fish for growth hormone (GH) has been considered as a potential technological improvement in aquaculture. In this study, a double-transgenic zebrafish was used to evaluate the effect of GH and its receptor (GHR) on muscle growth. Double transgenics reached the same length of GH transgenic, but with significantly less weight, featuring an unbalanced growth. The condition factor of GH/GHR-transgenic fish was lower than the other genotypes. Histological analysis showed a decrease in the percentage of thick muscle fibers in GH/GHR genotype of ∼ 80% in comparison to GH-transgenic line. The analysis of gene expression showed a significant decrease in genes related to muscle growth in GH/GHR genotype. It seems that concomitant overexpression of GH and GHR resulted in a strong decrease of the somatotrophic axis intracellular signaling by diminishing its principal transcription factor signal transducer and activator of transcription 5.1 (STAT5.1).

Rapid method for Growth Hormone Receptor exon 3 delete (GHRd3) SNP genotyping from archival human placental samples

Analysis of archival samples from cohorts of pregnant women may be key to discovering prognosticators of stillbirth and pregnancy/perinatal complications. Growth hormone (GH) and its receptor (GHR) are pivotal in feto-placental development and pregnancy maintenance. We report a rapid, optimized method for genotyping the GHR full-length versus exon 3-deleted isoform (GHRd3). TaqMan single nucleotide polymorphism (SNP) genotyping proved superior to standard multiplex polymerase chain reaction (PCR) in allele detection and GHR genotyping from archived samples, including those with poor genomic deoxyribonucleic acid quality/quantity such as formalin fixed, paraffin embedded, blood, and serum. Furthermore, this assay is suitable for high through put 96 or 384-well plate quantitative PCR machines with automated genotype calling software. The TaqMan genotyping assay can increase the data obtained from precious archival human samples.

Rapid method for growth hormone receptor exon 3 delete (GHRd3) SNP genotyping from archival human placental samples.

Analysis of archival samples from cohorts of pregnant women may be key to discovering prognosticators of stillbirth and pregnancy/perinatal complications. Growth hormone (GH) and its receptor (GHR) are pivotal in feto-placental development and pregnancy maintenance. We report a rapid, optimized method for genotyping the GHR full-length versus exon 3-deleted isoform (GHRd3). TaqMan single nucleotide polymorphism (SNP)genotyping proved superior to standard multiplex polymerase chain reaction (PCR) in allele detection and GHR genotyping from archived samples, including those with poor genomic deoxyribonucleic acid quality/quantity such as formalin fixed, paraffin embedded, blood, and serum. Furthermore, this assay is suitable for high through put 96 or 384-well plate quantitative PCR machines with automated genotype calling software. The TaqMan genotyping assay can increase the data obtained from precious archival human samples.

Double transgenic zebrafish for somatotrophic axis: a tool for muscle development and growth studies.

ZebrafishVol. 12, No. 3 TechnofishDouble Transgenic Zebrafish for Somatotrophic Axis: A Tool for Muscle Development and Growth StudiesAna C. Silva, Daniela V. Almeida, Marcio A. Figueiredo, and Luis F. MarinsAna C. SilvaSearch for more papers by this author, Daniela V. AlmeidaSearch for more papers by this author, Marcio A. FigueiredoSearch for more papers by this author, and Luis F. MarinsSearch for more papers by this authorPublished Online:15 May 2015https://doi.org/10.1089/zeb.2015.1090AboutSectionsView articleView Full TextPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail View article"Double Transgenic Zebrafish for Somatotrophic Axis: A Tool for Muscle Development and Growth Studies." Zebrafish, 12(3), pp. 268–269FiguresReferencesRelatedDetailsCited byReproductive parameters of double transgenic zebrafish (Danio rerio) males overexpressing both the growth hormone (GH) and its receptor (GHR)14 October 2016 | Transgenic Research, Vol. 26, No. 1 Volume 12Issue 3Jun 2015 InformationCopyright 2015, Mary Ann Liebert, Inc.To cite this article:Ana C. Silva, Daniela V. Almeida, Marcio A. Figueiredo, and Luis F. Marins.Double Transgenic Zebrafish for Somatotrophic Axis: A Tool for Muscle Development and Growth Studies.Zebrafish.Jun 2015.268-269.http://doi.org/10.1089/zeb.2015.1090Published in Volume: 12 Issue 3: May 15, 2015Online Ahead of Print:March 23, 2015PDF download

GH in the Central Nervous System: Lessons from the Growth Hormone Receptor Knockout Mouse

Various central nervous system (CNS) tissues express both growth hormone (GH) and its receptor (GHR), including those involved in memory and cognition. Studies show the presence of GHR in the pituitary, choroid plexus, hypothalamus, hippocampus, pituitary and the spinal cord during development and, to a lesser extent, in adults. This expression implies a role of GH signaling in growth, development and functionality of the CNS. While data on the function of GH in the CNS is sparse, several studies have been conducted using the GHR knockout (-/-) mouse in order to better understand this role. Abnormal growth hormone signaling in humans is the cause of various diseases that include Laron syndrome, GH deficiency and acromegaly. This article will review the research conducted using the GHR-/- mouse on the role of GH signaling in the CNS. Where possible, we will attempt to contextualize the animal data with respect to human disease.

Cellular and intracellular distribution of growth hormone in the adult chicken testis

Endocrine actions of growth hormone (GH) have been implicated during the development of adult testicular function in several mammalian species, and recently intracrine, autocrine, and paracrine effects have been proposed for locally expressed GH. Previous reports have shown the distribution of GH mRNA and the molecular heterogeneity of GH protein in both adult chicken testes and vas deferens. This study provides evidence of the presence and distribution of GH and its receptor (GHR) during all stages of spermatogenesis in adult chicken testes. This hormone and its receptor are not restricted to the cytoplasm; they are also found in the nuclei of spermatogonia, spermatocytes, and spermatids. The pattern of GH isoforms was characterized in the different, isolated germ cell subpopulations, and the major molecular variant in all subpopulations was 17kDa GH, as reported in other chicken extra-pituitary tissues. Another molecular variant, the 29kDa moiety, was found mainly in the enriched spermatocyte population, suggesting that it acts at specific developmental stages. The co-localization of GH with the proliferative cell nuclear antigen PCNA (a DNA replication marker present in spermatogonial cells) was demonstrated by immunohistochemistry. These results show for the first time that GH and GHR are present in the nuclei of adult chicken germinal cells, and suggest that GH could participate in proliferation and differentiation during the complex process of spermatogenesis.

SECRETION AND PROLIFERATIVE EFFECTS OF CHICKEN GROWTH HORMONE IN TESTICULAR CELL CULTURES TREATED WITH GHRH

Event Abstract Back to Event SECRETION AND PROLIFERATIVE EFFECTS OF CHICKEN GROWTH HORMONE IN TESTICULAR CELL CULTURES TREATED WITH GHRH Carlos G. Martínez-Moreno1, Luz M. López-Marín2, Martha E. Carranza1, Carlos Arámburo1 and Maricela Luna1* 1 Universidad Nacional Autonoma de Mexico, Institute of Neurobiology, Dept. of Molecular and Cellular Neurobiology, Mexico 2 Universidad Nacional Autónoma de México, Centro de Física Aplicada y Tecnología Avanzada, Mexico Recent findings showed the cytoplasmic and nuclear distribution of growth hormone (GH) and its receptor (GHR) in chicken testicular germ cells, suggesting an intracrine, autocrine and/or paracrine role for this hormone during spermatogenesis. The expression of testicular GH may be modulated by a variety of factors, including growth hormone releasing hormone (GHRH) and Pit-1. We analyzed the effect of GHRH (1, 10 and 100 nM, for 2 h) on GH release into the media of primary cell cultures derived from chicken testes at two developmental stages: during puberty (20 weeks, PC) and sexual maturity (32 weeks, MC). Released GH increased after GHRH treatment both in PC media (10.8±1, 13.4±2 and 14.5±2 ng/ml) and MC media (5.83±2.05, 7.6±0.6 and 8.5±2 ng/ml) in comparison to the corresponding controls (7.4±1 and 3.2±0.7 ng/ml, respectively). Western blot analyses were performed to characterize whether GHRH modulation involved secretion of particular GH isoforms. Interestingly, 15 kDa and 26 kDa GH variants were differentially modulated after 100 nM GHRH treatment, resulting in a 2.5 fold-increase in 15 kDa GH secretion, whereas a significant decrease was found for the 26 kDa variant release. On the other hand, GHRH (1, 10, 100 nM) stimulated proliferation of testicular cells in culture (2.7-, 3.6- and 2.0-fold, respectively, in comparison to the controls) as determined by the PCNA assay. Using the 3H-thymidine incorporation assay GH also increased the proliferation of testicular cells (by 118.7±18.1%, and 170.8±28%, and 102.1±15.7% at 1, 10 and 100 nM, respectively, when compared to 96.1±12.4% in the untreated controls). Altogether, these results suggest a role of GHRH and GH during chicken testicular cell proliferation, probably through autocrine/paracrine mechanisms. Acknowledgements This work was supported by grants CONACyT (F1-60296) and PAPIIT-UNAM (IN-210209), graduate fellowships from CONACyT (185024) and PDCB-UNAM and Alejandro Bayón Fund established by CA Keywords: autocrine/paracrine mechanisms, extrapituitary growth hormone, GHRH, Growth Hormone, proliferation, testicular cell cultures, testicular growth hormone variants Conference: NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology, Ann Arbor, United States, 13 Jul - 16 Jul, 2011. Presentation Type: Poster Topic: Gonadal development and gamete maturation Citation: Martínez-Moreno CG, López-Marín LM, Carranza ME, Arámburo C and Luna M (2011). SECRETION AND PROLIFERATIVE EFFECTS OF CHICKEN GROWTH HORMONE IN TESTICULAR CELL CULTURES TREATED WITH GHRH. Front. Endocrinol. Conference Abstract: NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology. doi: 10.3389/conf.fendo.2011.04.00094 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 23 Jul 2011; Published Online: 09 Aug 2011. * Correspondence: Dr. Maricela Luna, Universidad Nacional Autonoma de Mexico, Institute of Neurobiology, Dept. of Molecular and Cellular Neurobiology, Queretaro, Queretaro, 76230, Mexico, lunam@servidor.unam.mx Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract Supplemental Data The Authors in Frontiers Carlos G Martínez-Moreno Luz M López-Marín Martha E Carranza Carlos Arámburo Maricela Luna Google Carlos G Martínez-Moreno Luz M López-Marín Martha E Carranza Carlos Arámburo Maricela Luna Google Scholar Carlos G Martínez-Moreno Luz M López-Marín Martha E Carranza Carlos Arámburo Maricela Luna PubMed Carlos G Martínez-Moreno Luz M López-Marín Martha E Carranza Carlos Arámburo Maricela Luna Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. 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Expression and localization of growth hormone receptor in the oviduct of cyclic and pregnant pigs and mid-implantation conceptuses

Previously it was shown that growth hormone (GH) and its receptor (GH-R) are involved in growth-promoting events during early embryonic development. However, it is still unknown if GH-induced GH-R signalling may support other functions within the oviduct. The purpose of our study was to analyse GH-R expression and localization in the porcine oviduct during different stages of the oestrus cycle and pregnancy (days 2-3 post inseminationem to days 65-71). As shown by reverse transcription polymerase chain reaction (RT-PCR), GH-R is expressed in the porcine oviduct during all stages of the oestrus cycle and pregnancy, respectively. Additionally, GH-R mRNA was detected in porcine conceptuses collected at day 18 of pregnancy. Using immunohistochemistry, GH-R was exclusively localized to the epithelium of the porcine oviduct throughout all segments examined. Localization of GH-R was mainly observed in the cytoplasm of ciliated epithelial cells. Generally, the number of GH-R-positive cells was elevated in the periovulatory phase of the oestrus cycle. Except for the isthmic epithelium, staining intensity of GH-R-positive cells was highest at oestrus and markedly reduced at met- and dioestrous stages. In infundibular and ampullar segments, percentage of GH-R-positive cells was significantly higher at days 2-3 post inseminationem compared to days 65-71 of pregnancy. Furthermore, in porcine conceptuses on day 18 of pregnancy GH-R protein expression was almost exclusively localized to trophectoderm. Our data suggest that GH-R mRNA and protein expression in the porcine oviduct throughout the oestrus cycle and pregnancy may suggest other activities of GH not described previously. Specifically, autocrine or paracrine GH-induced GH-R signalling may be linked to ciliated cell homeostasis of the porcine oviduct. Additionally, our results indicate that GH-R expression in the pig trophectoderm may be responsible for trophoblastic elongation.

Growth hormone promotes proliferation of adult neurosphere cultures

Objectives Growth hormone (GH) and its receptor (GHR) are widely expressed in the CNS. During development, GH signaling regulates both proliferation of neural progenitor cells as well as their differentiation into neurons and glia. Here we have examined the effect of GH signaling on adult subventricular zone derived neural progenitor cells cultured as neurospheres. Design GH was added to adult wild-type (WT) neurosphere cultures and neurosphere growth measured using the MTT cell proliferation assay. To examine the influence of endogenous GH production on neural progenitors, neurospheres derived from GH receptor knockout (GHRKO) mice were examined by measuring neurosphere sizes and Ki67 and TUNEL immunoreactivity. In addition, neurosphere growth curves were compared following long term culture. Finally, the differentiation of WT vs. GHRKO neurospheres was compared using immunocytochemistry for βIII-tubulin and GFAP. Results While GH alone was insufficient to support neurosphere formation, it enhanced neurosphere growth by 20% in the presence of epidermal growth factor and fibroblast growth factor-2. Compared to wildtype neurospheres, GHRKO neurospheres were smaller, contained fewer proliferating cells and exhibited reduced self-renewal in long term culture. Addition of GH increased STAT5 phosphorylation levels in neurosphere cells. Upon differentiation, GHRKO neurospheres showed accelerated neurogenesis, although over time similar numbers of βIII-tubulin positive neurons were generated by cells of both genotypes. Conclusions GH functions as an autocrine mitogen in adult neurosphere cultures and promotes proliferation of neural progenitor cells as well as self-renewal of neurosphere cultures. In addition, signaling through the GHR appeared to delay neuronal differentiation in adult neurospheres.

Growth hormone and its receptor in human ovaries from fetuses and adults

To investigate the presence of growth hormone (GH) and its receptor (GH-R) in early developing follicles. Immunocytochemical and in situ hybridization study. Major tertiary care and referral academic centers. Ten ovarian samples from adults/girls aged 6-38 years and from 10 fetuses of women undergoing second and third trimester pregnancy terminations. None. Immunocytochemistry and in situ hybridization on paraffin sections of human ovaries from fetuses and women/girls. The proteins and the mRNA transcripts for GH and GH-R were detected in oocytes, granulosa (GC), and stroma cells from both sources (fetuses and women/girls), with low staining intensity only in a portion of the fetal GC. This is the first report of the expression of GH-R in human ovaries from fetuses as well as women/girls and of GH in human fetal ovaries. Be that as it may, further experiments should be conducted to elucidate if indeed GH is involved in the initiation of human primordial follicular growth.

Evolution of Receptors for Growth Hormone and Somatolactin in Fish and Land Vertebrates: Lessons from the Lungfish and Sturgeon Orthologues

Two cognate hormones, growth hormone (GH) and somatolactin (SL), control several important physiological processes in vertebrates. Knowledge about GH and its receptor (GHR) has accumulated over the last decades. However, much less is known about SL and its receptor (SLR). SL is found only in fish (including lungfish), suggesting that it was present in the common ancestor of vertebrates, but was lost secondarily in the lineage leading to land vertebrates after the lungfish branched off. SLR was suggested to be a duplicated copy of GHR acquired only in teleosts via the fish-specific genome duplication (FSGD). This scenario (i.e., the existence of SL but not SLR in the vertebrate ancestors) is intriguing but contested. In this study, we first evaluated the plausibility of this scenario through synteny analyses and found that the loci for GHR and SLR are located in syntenic genomic positions, whereas the loci for GH and SL are not. Next, we cloned GHRs of lungfish and sturgeon, which possess SL but did not undergo the FSGD (i.e., they should not possess SLR). Their phylogenetic positions in the GHR/SLR gene tree further support the fish-specific scenario for the GHR-SLR duplication. Interestingly, their sequences share greater similarity with teleost SLRs and reptilian/amphibian GHRs than with the GHRs of mammals, birds, and teleosts. On the basis of these results, we discuss the validity of the nomenclature of the teleost-specific copy of GHR as SLR and an ancestral receptor(s) for SL before the evolution of SLR during the FSGD.

Growth hormone (GH) receptors in prostate cancer: gene expression in human tissues and cell lines and characterization, GH signaling and androgen receptor regulation in LNCaP cells

Various hormones and growth factors have been implicated in progression of prostate cancer, but their role and the underlying molecular mechanism(s) involved remain poorly understood. In this study, we investigated the role of human growth hormone (GH) and its receptor (GHR) in human prostate cancer. We first demonstrated mRNA expression of GHR and of its exon 9-truncated isoform (GHR tr) in benign prostate hyperplasia (BPH) and prostate adenocarcinoma patient tissues, as well as in LNCaP, PC3 and DU145 human prostate cancer cell lines. GHR mRNA levels were 80% higher and GHR tr only 25% higher, in the carcinoma tissues than in BPH. Both isoforms were also expressed in LNCaP and PC3 cell lines and somewhat less so in DU145 cells. The LNCaP cell GHR protein was further characterized, on the basis of its M r of 120 kDa, its binding to two different GHR monoclonal antibodies, its high affinity and purely somatogenic binding to 125I-hGH and its ability to secrete GH binding protein, all characteristic of a functional GHR. Furthermore, GH induced rapid, time- and dose-dependent signaling events in LNCaP cells, including phosphorylation of JAK2 tyrosine kinase, of GHR itself and of STAT5A (JAK2-STAT5A pathway), of p42/p44 MAPK and of Akt/PKB. No effect of GH (72 h) could be shown on basal or androgen-induced LNCaP cell proliferation nor on PSA secretion. Interestingly, however, GH caused a rapid (2–12 h) though transient striking increase in immunoreactive androgen receptor (AR) levels (≤5-fold), followed by a slower (24–48 h) reduction (≤80%), with only modest parallel changes in serine-phosphorylated AR. In conclusion, the GH-induced activation of signaling pathways, its effects on AR protein in LNCaP cells and the isoform-specific regulation of GHR in prostate cancer patient tissues, suggest that GH, most likely in concert with other hormones and growth factors, may play an important role in progression of human prostate cancer.

Growth hormone (GH)/GH receptor expression and GH-mediated effects during early bovine embryogenesis.

Pituitary growth hormone (GH) stimulates postnatal growth and metabolism. The role of GH and its receptor (GHR) during prenatal development, however, is still controversial. As shown by reverse transcription polymerase chain reaction (RT-PCR), bovine in vitro fertilization embryos synthesized the transcript of GHR from Day 2 of embryonic life onwards. Real time RT-PCR revealed that synthesis of GHR mRNA was increased 5.9-fold in 6-day-old embryos compared with 2-day-old embryos. Using in situ hybridization, the mRNA encoding GHR was predominantly localized to the inner cell mass of blastocysts. The GHR protein was first visualized 3 days after fertilization. GH-specific transcripts were first detected in embryos on Day 8 of in vitro culture. As shown by transmission electron microscopy, GH treatment resulted in elimination of glycogen storage in 6- to 8-day-old embryos and an increase in exocytosis of lipid vesicles. These results suggest that a functional GHR able to modulate carbohydrate and lipid metabolism is synthesized during preimplantation development of the bovine embryo and that this GHR may be subject to activation by embryonic GH after Day 8.

Expression of growth hormone receptor in the bovine mammary gland during prenatal development.

Growth hormone (GH) is known to play a key role in postnatal growth and differentiation. The role of GH and its receptor (GHR) in prenatal development, however, is still controversial. Using reverse transcription polymerase chain reaction (RT-PCR), in situ hybridization (ISH) and immunohistochemistry we demonstrated the presence of GHR mRNA and protein in bovine mammary glands during fetal development. RT-PCR revealed GHR transcripts in fetal mammary glands from the third to the ninth month of pregnancy. By non-radioactive ISH, GHR mRNA was localized in the glandular epithelium, the surrounding mesenchymal cells, endothelial cells of vessels and in the stratum basale of the epidermis of fetal mammary glands. From the sixth month of fetal life onwards, GHR transcripts were also found in the cytoplasm of adipocytes. Immunohistochemical studies using the monoclonal antibody mAb 263 revealed the same distribution pattern as the mRNA. Our results imply that the growth hormone receptor is distinctly expressed in the immature mammary gland, suggesting that GH is involved in growth and differentiation of the fetal mammary gland.

Intracellular traffic of growth hormone (GH) and its receptor (GHR) in CHO cells transfected with GHR cDNA: A confocal microscopic study

Intracellular traffic of growth hormone (GH) and its receptor (GHR) in CHO cells transfected with GHR cDNA: A confocal microscopic study