The current study focuses on molecular cloning, expression and structural characterization of growth hormone-receptor (GHR) and its extracellular domain as growth hormone binding protein (GHBP) from the liver of Nili-Ravi buffalo (Bubalus bubalis; Bb). RNA was isolated, genes were amplified by reverse transcriptase-polymerase chain reaction and sequence was characterized. The BbGHR sequence showed three amino acid variations in the extracellular domain when compared with Indian BbGHR. For the production of full length BbGHR and BbGHBP in Escherichia coli (E. coli) BL21 (RIPL) Codon Plus, expression plasmids were constructed under the control of T7lac promoter and isopropyl β-D thiogalactopyranoside was used as an inducer. BbGHR and BbGHBP were expressed as inclusion bodies at ~ 40% and > 30% of the total E. coli proteins, respectively. The BbGHBP was solubilized and refolded by dilution method using cysteine-cystine redox potential. The recombinant BbGHBP was purified and biological activity was checked on HeLa cell lines showing increase cell proliferation in the presence of ovine GH (oGH), hence justifying the increase in the half-life of GH in the presence of BbGHBP. For the molecular interactions of oGH-BbGHBP multiple docking programs were employed to explore the subsequent interactions which showed high binding affinity and presence of large number of hydrogen bonds. Molecular Dynamics studies performed to examine the stability of proteins and exhibited stable structures along with favorable molecular interactions. This study has described the sequence characterization of BbGHR in Nili-Ravi buffaloes and hence provided the basis for the assessment of GH-GHR binding in other Bovidae species.
Growth hormone (GH) levels were measured after a 75g oral glucose load (OGTT) in normal adults, patients with impaired glucose tolerance (IGT), insulin-dependent diabetes mellitus (IDDM) and acromegaly. Nadir GH levels at 2-hour post-OGTT in normal subjects ranged from 0.4 to 8.4 mIU/L, the 95% confidence interval being 0.4-4.4 mIU/L. In IGT and IDDM subjects basal fasting GH levels were not significantly different from normal and did not alter during OGTT. The high fasting GH level measured in one each of the IGT and IDDM patients was suppressible at 1-hour after glucose intake. In contrast, acromegalic patients had elevated fasting GH levels (11.8-178 mIU/L) although in 3 patients, the levels were mildly elevated and overlapped with normal. OGTT failed or only partially suppressed GH secretion in all acromegalics. Therefore, elevated fasting GH levels are not diagnostic and OGTT is required for accurate diagnosis and assessment of treatment of acromegalic patients.
It is now recognized that growth hormone (GH) deficiency in adults represents a distinct clinical syndrome that encompasses reduced psychological well-being as well as specific metabolic abnormalities. The latter features, which include hypertension, central obesity, insulin resistance, dyslipidaemia and coagulopathy, closely resemble those of metabolic insulin resistance syndrome. The increased cardiovascular morbidity and mortality demonstrated in these GH-deficient (GHD) adults reinforce the close association between the two syndromes. Replacement of GH in GHD adults has resulted in a marked reduction of central obesity and significant reduction in total cholesterol but little change in other risk factors, in particular insulin resistance and dyslipidaemia. The persistent insulin resistance and dyslipidaemia, together with the elevation of plasma insulin levels and lipoprotein (a) with GH replacement in these subjects are of concern. Long-term follow-up data are required to assess the impact of GH replacement on the cardiovascular morbidity and mortality of GHD adults. Further exploration of the appropriateness of the GH dosage regimens currently being employed is also indicated.
Matched MeSH terms: Human Growth Hormone/metabolism
The role of steroid/thyroid hormones in the regulation of endocrine cells at the level of the pituitary has remained unclear. Therefore, using single-cell quantitative real-time PCR, we examined absolute amounts of transcripts for nuclear receptors [estrogen receptors (ERs) alpha, beta, and gamma; androgen receptors (ARs) a and b; glucocorticoid receptors (GRs) 1, 2a, and 2b; and thyroid hormone receptors (TRs) alpha1, alpha2, and beta] in pituitary cells of immature (IM) and mature (M) male tilapia, Oreochromis niloticus. In the two reproductive stages, ACTH cells expressed only ERbeta, whereas all other pituitary cell types expressed ERalpha + beta, and a subpopulation coexpressed ARa, ARb, GR1, GR2b, and TRbeta but lacked ERgamma, GR2a, TRalpha1, and TRalpha2. IM males had high percentages of LH cells (IM 46.0% vs. M 10.0%), GH cells (IM 23.3% vs. M 7.9%), and prolactin cells (IM 68.8% vs. M 6.0%) with ERbeta, and TSH cells (IM 19.2% vs. M 0.0%) and MSH cells (IM 25.6% vs. M 0.0%) with ERalpha + TRbeta. A high percentage of FSH cells in IM males expressed ERbeta (IM 46.9% vs. M 18.8%), and FSH cells in M males showed significantly high GR1 transcripts (IM 76.0 +/- 5.0 vs. M 195.0 +/- 10.7 copies per cell; P < 0.05), suggesting that FSH cells are regulated differently in the two reproductive stages. Coexpression of ERalpha + beta in high percentages of cells of the GH family (GH, IM 43.8% vs. M 14.3%; prolactin, IM 8.3% vs. M 59.7%; somatolactin, IM 22.2% vs. M 42.2%) suggests that the expression of both ERs is important for functionality. Thus, differential coexpression of genes for nuclear receptors in subpopulations of pituitary cell types suggests multiple steroid/thyroid hormone regulatory pathways at the level of the pituitary during the two reproductive stages.
Hormones are known to influence various body systems that include skeletal, cardiac, digestive, excretory, and immune systems. Emerging investigations suggest the key role played by secretions of endocrine glands in immune cell differentiation, proliferation, activation, and memory attributes of the immune system. The link between steroid hormones such as glucocorticoids and inflammation is widely known. However, the role of peptide hormones and amino acid derivatives such as growth and thyroid hormones, prolactin, dopamine, and thymopoietin in regulating the functioning of the immune system remains unclear. Here, we reviewed the findings pertinent to the functional role of hormone-immune interactions in health and disease and proposed perspective directions for translational research in the field.