Different Combinations Of Hormones Research Articles

Deciphering the roles of triiodothyronine (T3) and thyroid-stimulating hormone (TSH) on cardiac electrical remodeling in clinical and experimental hypothyroidism.

Hypothyroidism is the most frequent endocrine pathology. Although clinical or overt hypothyroidism has been traditionally associated to low T3 / T4 and high thyrotropin (TSH) circulating levels, other forms exist such as subclinical hypothyroidism, characterized by normal blood T3 / T4 and high TSH. In its different forms is estimated to affect approximately 10% of the population, especially women, in a 5:1 ratio with respect to men. Among its consequences are alterations in cardiac electrical activity, especially in the repolarization phase, which is accompanied by an increased susceptibility to cardiac arrhythmias. Although these alterations have traditionally been attributed to thyroid hormone deficiency, recent studies, both clinical trials and experimental models, demonstrate a fundamental role of TSH in cardiac electrical remodeling. Thus, both metabolic thyroid hormones and TSH regulate cardiac ion channel expression in many and varied ways. This means that the different combinations of hormones that predominate in different types of hypothyroidism (overt, subclinic, primary, central) can generate different forms of cardiac electrical remodeling. These new findings are raising the relevant question of whether serum TSH reference ranges should be redefined.

تکثیر غیرجنسی ماریتیغال (Silybum marianum L.) از طریق باززایی مستقیم در شرایط درونشیشهای

Silybum marianum L., from fam. asteraceae, is a very important medicinal plant in the pharmaceutical industry due to its active ingredient silymarin. Silymarin is very effective in treating the liver diseases, hepatitis, and cardiovascular disorders. Since the potential and production speed of this medicinal compound is low in habitats under natural conditions, the use of genetic engineering and production of transgenic plants using the various techniques such as tissue culture has been considered in this plant. The first step in this direction is to obtain an in vitro regeneration protocol. In this study, the leaf explants obtained from the Hungarian cultivar of S. marianum were evaluated for the direct regeneration affected by different combinations of hormones. Six weeks after the culture, the highest shooting (57%) was observed in the ½ MS medium containing 0.4 mg l-1 zeatin, 0.2 mg l-1 BAP, and 0.2 mg l-1 NAA. The shoots were then transferred to the root culture medium with the different hormonal treatments. The results showed that the best treatment to obtain the long and high roots was the ½ MS medium containing 0.25 mg l-1 NAA and 2 g l-1 activated charcoal. The seedlings obtained from the direct regeneration grew well after transplanting into the soil.

Оптимизация протокола микроклонального размножения магнолии Суланжа (Magnolia × soulangeana Soul.-Bod.)

This study was aimed to develop an efficiently repetitive protocol for micropropagation of Magnolia × soulangeana using shoot meristem. The effective scheme of bud surface sterilization was found. In our opinion the best sterilizing agent was thimerosal in concentration of 0,1 %. After growing in vitro cultures on different combinations of hormones, mediums supplemented with BAP, IAA, NAA, IBA were found to be most efficient and productive combination for shoot proliferation. MS medium with half salt composition showed itself as the most effective composition for shoot initiation in vitro. The most adequate for shoot multiplication was QL medium with adding BAP (1 mg/l). The proliferated shoots were transferred to different root induction media, which resultantly showed that WPM media supplemented with NAA (0.5 mg/l) was the most efficient root inducing media. Rooted plants were adapted to the green house conditions. For these purposes we used substrate consisted of turf, soil and sand in equal parts. Finally, these plants were successfully established in soil.

Determination of suitable microspore stage and callus induction from anthers of kenaf (Hibiscus cannabinus L.).

Kenaf (Hibiscus cannabinus L.) is one of the important species of Hibiscus cultivated for fiber. Availability of homozygous parent lines is prerequisite to the use of the heterosis effect reproducible in hybrid breeding. The production of haploid plants by anther culture followed by chromosome doubling can be achieved in short period compared with inbred lines by conventional method that requires self pollination of parent material. In this research, the effects of the microspore developmental stage, time of flower collection, various pretreatments, different combinations of hormones, and culture condition on anther culture of KB6 variety of Kenaf were studied. Young flower buds with immature anthers at the appropriate stage of microspore development were sterilized and the anthers were carefully dissected from the flower buds and subjected to various pretreatments and different combinations of hormones like NAA, 2,4-D, Kinetin, BAP, and TDZ to induce callus. The best microspore development stage of the flower buds was about 6–8 mm long collected 1-2 weeks after flower initiation. At that stage, the microspores were at the uninucleate stage which was suitable for culture. The best callus induction frequency was 90% in the optimized semisolid MS medium fortified with 3.0 mg/L BAP + 3.0 mg/L NAA.

Differences in capacities of in vitro organ regeneration between two Arabidopsis ecotypes Wassilewskija and Columbia

In vitro organogenesis is well-controlled and thus provides an ideal system to study mechanisms of plant organ development. Although it has been well investigated for a long time that exogenous hormones play important roles in determining the types of organs regenerated in vitro, there is currently limited information available for other key factors that mediate de novo organ regeneration. Here, we reported simple and efficient one-step processes for evaluating capacities of inflorescence stem-derived in vitro organogenesis between two different ecotypes in Arabidopsis. Different types of organs, including shoots and roots were initiated from inflorescence stem explants cultured on the media containing 216 combinations of exogenous auxin and cytokinin. Further, we showed that Wassilewskija ecotype had the much higher shoot regeneration capacity than Columbia with different combinations of hormones, indicating that the ecotype is an essential factor determining de novo organogenesis. Our results also suggested that the defined expression patterns of genes involved in auxin and cytokinin biosynthesis were correlated with the variations in organogenesis capacities between the two ecotypes. Thus, in vitro organogenesis is likely regulated by ecotypes through mediating endogenous hormonal biosynthesis.

<i>In vitro</i> study of <i>Tinospora cordifolia</i> (Willd.) Miers (Menispermaceae)

In vitro study was carried out in an important medicinal plant Tinospora cordifolia (Willd.) Miers belonging to the family: Menispermaceae. Vegetative parts such as stem, leaf and nodal explants were excised from an elite in vivo grown mature plant and thereafter cultured on Murashige-Skoog (MS) medium supplemented with different hormonal concentrations for callus induction and organogenesis. Callus formation occurred from nodal segments, leaf and inter-node explants when planted on different combinations of hormones. Tinospora cordifolia showed response for in vitro shoot growth from the nodal segment. The best shoot growth was observed on MS medium supplemented with kinetin (1.5 mg/l). Similarly, the best result for root induction was obtained on MS medium supplemented with 6-benzylaminopurine (1.0 mg/l) and naphthaleneacetic acid (2.5 mg/l). Key-words: callus induction; explants; medicinal plant; MS medium; tissue culture.DOI: 10.3126/botor.v6i0.2918 Botanica Orientalis - Journal of Plant Science (2009) 6: 103-105

Micropropagation of Aloe vera L. Grown in South Iran

Aloe vera L. is a medicinal plant grown in different parts of the world. Several papers have reported the micropropagation of this plant and its response to different combinations of hormones. In this research, we used A. vera plants grown in south Iran. MS culture medium with twenty-three combinations of hormones were used, including some of those employed previously by other researchers. Ten media showed positive results and the best result was obtained using Kin (1 mg L(-1))+IAA (0.1 mg L(-1)) which has not been reported before. Produced plantlets rooted in free hormone MS medium and transferred into soil. The survival rate was 83%.

Insulin‐Like Factor 3: A Novel Circulating Hormone of Testicular Origin in Humans

Insulin-like factor 3 (INSL3) affects testicular descent. Mutations in the INSL3 gene or its receptor, LGR8/GREAT, can cause cryptorchidism. Expression of LGR8/GREAT in different tissues and production of INSL3 by adult-type Leydig cells suggest additional roles for this hormonal system in adults. We used a novel radioimmunoassay kit to measure INSL3 concentrations in the serum of normal men and those with different testicular pathologies. We demonstrate that INSL3 circulates in adult men and is almost exclusively of testicular origin. Subjects with severe testicular damage (infertility) produce small amounts of INSL3, and concentrations of this hormone seem to reflect the functional status of the Leydig cells. Analysis of men treated with different combinations of hormones of the hypothalamus-pituitary-testis axis suggests that the production of INSL3 is related to the luteinizing hormone.

A Novel Circulating Hormone of Testis Origin in Humans

Insulin-like factor 3 (INSL3) is a member of the relaxin-insulin family, and it is expressed in pre- and postnatal Leydig cells of the testis. This peptide affects testicular descent during embryonic development, and mutations in INSL3 gene or its receptor LGR8 (leucine-rich repeat-containing G protein-coupled receptor 8)/GREAT (G protein-coupled receptor affecting testicular descent) cause cryptorchidism in humans. The expression of LGR8/GREAT in different tissues and the production of INSL3 also by adult-type Leydig cells suggest additional roles of this hormonal system in adulthood. In this preliminary report we performed the first analysis in humans of INSL3 using a novel RIA kit to measure INSL3 concentrations in serum of normal men and with different testicular pathologies. The results show that INSL3 is circulating in adult men, and it is almost exclusively of testicular origin. Subjects with severe testicular damage, such as men with severe infertility, produce low amount of INSL3, and the concentrations of this hormone seem to reflect the functional status of the Leydig cells. In particular, INSL3 concentrations may be an even more sensitive marker of Leydig cell function than testosterone itself. Analysis of men treated with different combinations of hormones of the hypothalamus-pituitary-testis axis suggests that the production of INSL3 is related to LH in a manner similar to that of the LH-testosterone axis.

The new plant physiology-molecular approaches to studying hormonal regulation of plant development

In early botany, the study of morphogenesis in higher plants started at the level of the whole plant and its organs, describing their life cycle and the formation of the vegetative and generative organs during plant development. This stage of morphology was followed by that of physiology, in which experimental interference with developmental processes aimed at the analysis of causal relationships in plant morphogenesis. The past century offers beautiful examples of sophisticated experimental analysis of such developmental processes as, e.g., apical dominance and flower induction. It became apparent that plant metabolism, growth and development are genetically determined, and that the expression of the genetic information is dependent upon and modulated by internal and environmental factors such as, e.g., hormones and light. Neither the nature of the genes and the extent of their expression in particular developmental processes, nor the mechanism of action of the endogenous growth-regulating substances mediating internal and external signals were understood, however, although it seemed reasonable to assume that hormones influence developmental processes by bringing about changes in gene expression. Application of biochemical knowledge and methodology allowed for extension of experimentation at the cellular and subcellular levels, leading in several cases to the unravelling of hormonal or light-induced effects on enzyme activities in metabolic pathways. However, the significance of research at the protein level for the explanation of morphogenetic effects at the organ or whole-plant level has been severely limited by the correlative nature of the argumentation. The evidence is largely derived from simultaneously occurring variations at both levels, but apart from such correlations a firm causal argument cannot be obtained from combining physiological and biochemical data alone. Moreover, cell division, extension and differentiation, as well as the formation of organs and the spatial and temporal integration of various meristematic activities all depend on the interplay between various hormonal signals. Different combinations of hormones may act independently, synergistically, or antagonistically, and can influence each other’s metabolism, recognition by cellular receptors, or signal-transduction pathways. These complex interactions stem in part from the stochastic nature of hormonal regulation in plants itself (Trewavas 1991) and give rise to the plasticity of plant development, in which the pattern of growth and development is open to modulation by internal and external constraints and growth of new organs is invariably linked to loss of function of old organs (Woolhouse 1978).

Induction of differentiation in a rat mammary epithelial stem cell line by dimethyl sulphoxide and mammotrophic hormones.

Rama 25 is a clonal epithelial cell line derived from a dimethylbenzanthracene-induced rat mammary adenocarcinoma. In the presence of the mammotrophic hormones, insulin, hydrocortisone, estrogen and prolactin, Rama 25 produces small amounts of casein and forms domes at a low rate. The rates of both these processes can be greatly increased by the addition of dimethyl sulphoxide or hexamethylenebisacetamide which are also known to induce the differentiation of Friend erythroleukemia cells. Other compounds which stimulate the differentiation of Rama 25 cells include linoleic acid and 6-thioguanine. The intracellular pathways triggering changes in the two markers of differentiation are partially separable using different combinations of hormones, prolactin and hydrocortisone being the most important for the production of casein and the formation of domes respectively. The kinetics of differentiation, as judged by the appearance of these two markers, are characterised by two phases, a fixed period of 8 h (lag phase), the length of which is independent of the dimethyl sulphoxide concentration and a second phase where their rates are dependent on the concentration of dimethyl sulphoxide. Rama 25 cells do not become committed to differentiate during this lag phase but increasing numbers of cells do so after this period. We suggest that the differentiation processes occur in two stages. The first stage, involving the inducer, commits Rama 25 cells to a new differentiated state. The second stage, involving the hormones, modulates the expression of different markers of this state. Both casein production and dome formation can be blocked by inhibitors of DNA synthesis and show reciprocal changes with the rates of cellular DNA synthesis. Thus, in its hormonal and DNA synthetic requirements for differentiation, Rama 25 cells appear to resemble some of the mammary epithelial cells of mature virgin rats.

Screening for Barley Mutants With Altered Hormone Sensitivity in Their Aleurone Layers

A method, based on the diffusion assay of alpha-amylase on agar plates, was developed to screen for barley (Himalaya) mutants with altered sensitivity to gibberellic acid (GA(3)) or abscisic acid (ABA) in their aleurone layers. The seeds produced by sodium azide-mutagenized barley were screened for their ability to synthesize and secrete alpha-amylase when treated with different combinations of hormones. Various GA(3)-insensitive or supersensitive, ABA-insensitive, temperature-dependent GA(3)-insensitive, and constitutive mutants have been identified. Several stable mutants with altered GA(3) sensitivity were recovered. Two of the homozygous GA(3)-insensitive mutants have been preliminarily characterized. The GA(3)-enhanced production of alpha-amylase and release of phosphatase are hampered in these mutants. However, they have normal stem height, and the uptake of GA(3) by their aleurone layers appears to be the same as that of wild-type barley. They are most likely regulatory mutants affecting both alpha-amylase synthesis and phosphatase release.

Application of Chemicals in Organic Solvents to Dry Seeds

Various chemicals were applied to dry seeds by means of organic solvents. The gibberellic acid-treated (1 mm) lettuce seeds (Lactuca sativa L.) germinated nearly 100% in the dark even after prolonged storage, and those treated with abscisic acid (1 mm or 0.5 mm) failed to germinate in the light. The seedlings emerging from morphactin-treated (1 mm) cucumber seeds (Cucumis sativus L.) exhibited profound changes in morphology. Different combinations of hormones applied to lettuce seeds caused a promotion or an inhibition of germination. Germination promotion or inhibition studies showed that the applied chemicals could be removed by washing with an organic solvent or water. Progressively larger amounts of chemicals were removed with increasing periods of washing. Thus the chemical appeared to penetrate the seed to some degree. The potential of the organic solvent method is discussed.

Regulation of Protein Synthesis in Chick Oviduct: I. INDEPENDENT REGULATION OF OVALBUMIN, CONALBUMIN, OVOMUCOID, AND LYSOZYME INDUCTION

Egg white protein synthesis is induced and maintained in oviduct magnum of immature female chicks by administering gonadal steroid hormones. The relative rate of synthesis of four egg white proteins (ovalbumin, conalbumin, ovomucoid, and lysozyme) was measured by culturing magnum explants with radioactive amino acids followed by specific immunoprecipitation of each of the egg white proteins. Induction of these proteins was studied as a function of time, hormonal dose, and hormonal combination. A combination of estrogen, progesterone, and testosterone was found which would induce the relative rate of synthesis of each of the four egg white proteins to a level that closely approximates that observed in laying hens; this combination also promotes maximal magnum growth. The synthesis of these proteins is not strictly coordinated, since the rate of synthesis of one or more of these proteins can change relative to the others, although they are all synthesized in the same cell. Noncoordinate protein synthesis is exemplified by the changing ratio of conalbumin to ovalbumin synthesis during both primary and secondary stimulation with estrogen. The ratio of synthesis of these two proteins also changes as a function of the dosage of hormone administered. Furthermore, different combinations of hormones can produce noncoordinate synthesis; for example, the synthesis of ovomucoid and conalbumin is increased relative to ovalbumin when either progesterone or testosterone are administered along with estrogen. The most likely explanation for the change in the ratio of ovalbumin to conalbumin synthesis observed during hormonal stimulation is the 2-fold difference in the rates of degradation of their mRNAs. In contrast, changes in mRNA synthesis or activation best account for the preferential induction of conalbumin synthesis by low doses of estrogen, and the increased rates of conalbumin and ovomucoid synthesis which are produced by supplementing estrogen with either progesterone or testosterone. The results suggest that a single regulatory site for the control of egg white synthesis is unlikely since several of these proteins appear to be under independent control.