Journal ArticleDOI
Association between Plasma Level of Growth Hormone and Sex Differentiation of Hepatic Steroid Metabolism in the Rat
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TLDR
The hypothesis that the plasma pattern of growth hormone (GH) regulates hepatic steroids metabolism in the rat was studied in two different animal models and under conditions which lead to feminization of hepatic steroid metabolism.Abstract:
The hypothesis that the plasma pattern of growth hormone (GH) regulates hepatic steroid metabolism in the rat was studied in two different animal models: 1) different plasma patterns of GH were achieved by the administration of human GH at different frequencies or by infusing the hormone continuously by means of Alzet osmotic minipumps to hypophysectomized female rats and 2) the plasma pattern of GH in animals with an intact pituitary gland was investigated under conditions which lead to feminization of hepatic steroid metabolism. The pattern of GH was determined by studying minimum and maximum plasma GH levels in blood samples taken from the tip of the tail at various times. After continuous administration of human GH to hypophysectomized female rats, the liver microsomal metabolism of 4-[4-14C]androstene-3,17-dione was feminized, e.g. the ratio between 5α-reductase and 16α-hydroxylase activities (5α/16α ratio) increased from 2.45 ± 0.21 to 31.2 ± 1.76. Similar results were observed when the animals were...read more
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Journal ArticleDOI
Sexual dimorphism in the control of growth hormone secretion.
TL;DR: A feminization of the liver develops after continuous, but not intermittent, administration of GH to hypophysectomized rats, suggesting that high, infrequent GH pulses with low plasma GH levels in between promotes growth more effectively than an intermediate, rather constant level of plasma GH.
Journal ArticleDOI
Sex Differences in the Expression of Hepatic Drug Metabolizing Enzymes
TL;DR: Key features of the cell signaling and molecular regulatory mechanisms by which sex-dependent plasma GH patterns impart sex specificity to the liver are discussed, which provide novel insights into the physiological regulation of both xenobiotic and endobiotic metabolism.
Journal ArticleDOI
Child health, developmental plasticity, and epigenetic programming.
Zeev Hochberg,Robert Feil,M. Constancia,Mario F. Fraga,Claudine Junien,Jean-Claude Carel,P. Boileau,Y. Le Bouc,Cheri Deal,Karen A. Lillycrop,R. Scharfmann,Allan Sheppard,Michael K. Skinner,Moshe Szyf,Robert A. Waterland,David J. Waxman,E. Whitelaw,Ken K. Ong,Kerstin Albertsson-Wikland +18 more
TL;DR: Translational epigenetic research in child health is a reiterative process that ranges from research in the basic sciences, preclinical research, and pediatric clinical research and creates potential applications in clinical practice: the development of epigenetic biomarkers for early diagnosis of disease, the ability to identify susceptible individuals at risk for adult diseases, and theDevelopment of novel preventive and curative measures that are based on diet and/or novel epigenetic drugs.
Journal ArticleDOI
Molecular Endocrinology of Hydroxysteroid Dehydrogenases
TL;DR: This work states that the 3β-HSD/KSI cDNAs and 3α- HSD deficiencies are likely to be driven by the same underlying mechanism, namely phosphorylation of H2O by the H3O2 “spatially aggregating” substance.
Journal ArticleDOI
Possible underlying mechanisms of sexual dimorphism in the immune response, fact and hypothesis.
TL;DR: It is quite possible that the increased immune response in females allows them to compensate for the increased physiological stress which accompanies reproduction, and the final outcome would thus be the assurance of reproductive success of the species.
References
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Journal Article
Protein Measurement with the Folin Phenol Reagent
TL;DR: Procedures are described for measuring protein in solution or after precipitation with acids or other agents, and for the determination of as little as 0.2 gamma of protein.
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A method for producing specific antisera with small doses of immunogen.
TL;DR: The method has succeeded in producing specific antisera to the subunits of HCG and testosterone conjugates with one immunization of 20 to 100 μg of immunogen, and the potential of the method for producing specificantisers to glycoprotein and other hormones with limited amounts of purified material prompts this report.
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Enzymatic iodination of polypeptides with 125I to high specific activity.
J.I. Thorell,B.G. Johansson +1 more
TL;DR: Polypeptide hormones radioiodinated by this technique retained their immunological reactivity and were used in radioimmunoassays with good results.
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Evidence for an endogenous ultradian rhythm governing growth hormone secretion in the rat.
TL;DR: It is suggested that GH secretion in the rat is governed by an endogenous ultradian rhythm, with a periodicity of approximately 3.3 h, and that the alternation of light and darkness probably serves as a Zeitgeber which sets the biological "clock" for GH secretion, but is not necessary for maintenance of the basic rhythm.
Journal ArticleDOI
Age- and Sex-Related Differences in Episodic Growth Hormone Secretion in the Rat*
TL;DR: Sequential blood samples were obtained from undisturbed, unrestrained, male and female rats of different ages from intrajugular or intraaortic cannulae implanted 4 days before experimentation and plasma GH was determined by RIA.