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Insulin pertaining growth and growth hormone as well as sex steroids as seen in I-axis in adult people
By Fisker S, Vestergaard E, Christensen JJ, Jorgensen JO, Christiansen JS, Ovesen P.
The department of diabetes and endocrinology in the medical department as well as department of obstetrics and gynecology in Arhus University Hospital located in Denkar, Arhus. Email: jolj@dadlnet.dk
The growth factor resembling insulin growths in normal adults are not different when it comes to men and women. However, the spontaneous production of human growth hormone is twice higher in women. Women who are deficient in growth hormones and have not been treated for the same have lower IGF-I level in comparison with men. The serum called IGF-I increases much lesser even during growth hormone replacement therapy. It has been found from such hgh findings that women have a higher resistance to human growth hormone. When oral oestrogen is administrated in women with post-menopausal symptoms, it curtails the production of hepatic type of IGF-I. It also causes the pituitary gland to release more growth hormones. Women who have GHD and are being orally administered oestrogen replacement therapy have reduced concentrations of IGF-I. This means that more human growth hormones are needed to achieve the optimal levels of IGF-I. Due to oestrogen levels, the IGF-I of hepatic type is curtailed in production. This is why there is a difference in the sensitivity to growth hormones in men and women. At other points, various sex steroids can interact with growth hormones as well as IGF and HGH related research also shows the relation between testosterone in enhancing IGF-I production. A certain amount of androgens is required in the body to sustain hepatic type of IGF-I manufacture. It is yet to be proven if oestrogen replacement medications should be discontinued in women or not.
Using testosterone supplements in older men induces more secretion of growth hormones as well as IGF-I without hampering efficiency of peptidyl secretagogue.
By Miles JM, Keenan DM, Veldhuis JD, Bowers CY.
Internal Medicine department at Graduate Schools of Medicine and Mayo Medical, Mayo Clinic General Clinical Research Center, Rochester in Minnesota, USA. Email: veldhuis.johannes@mayo.edu
The aim of the experiment is to determine that testosterone supplements increase secretion of both IGF-I as well as growth hormones through unknown means. The subjects of this experiment are healthy older males. The first hypothesis is that testosterone increases growth hormone secretion by releasing HGH inducing peptides. This is combined with arginine to curtail outflow of somatostatin. The second hypothesis is that testosterone increases peptidyl secretagogue effects and thus curtails resistance because of hypothalamic somatostatin. The third hypothesis is that AVF or fatty deposits in the abdomen cannot be used to determine growth hormone secretion because of secretagogue. The design used were crossover designs of double blind placebo as against administration of testosterone in healthy older males. The methods used were conducting deconvolution analysis to find out the basal levels of HGh secretions as well as time shape and integral bursts of human growth hormone secretions. The results obtained showed that when comparing placebo versus testosterone in men between 60 and 77 years of age showed differing values of growth hormones. The placebo men showed concentrations of growth hormones less than 0.01 and IGF-I of 0.003 while basal secretions were less than 0.005 and pulsatile less than 0.01. Thus, in effect, testosterone did not change either rank order or absolute value of efficiency of secretagogue. Indications from waveform reconstruction showed that every pair of stimulus enhanced initial secretions of growth hormones within one burst. The P was less than 0.01. Analysis of regression showed more inverse association between the burst of human growth hormone secretions and tomography aided computer estimations of AVF. This was after the stimulation with the help of l-arginine/GHRH once testoserone administration was completed. The results clearly showed that concentrations of Supraphysiological testosterone increase both IGF-I as well as growth hormone secretions in older males without affecting somatotrope responses to combined or single GHRH and GHRP-2 drive. Thus, this suggests the multifactorial mechanism of upregulation of testosterone.
Insulin sensitivity improvements without any changes in concomitant body composition as well as cardiovascular risk markings after administration of low doses of growth hormones in adults having severe deficiency of growth hormones.
By Yuen KC, Twickler TB, White DK, Frystyk J, Koppeschaar HP, Murgatroyd PR, Harris PE, Dunger DB, Fryklund L
From the Paediatrics and Endocrinology department at Addenbrooke’s Hospital in Cambridge UK.
The aim of the experiment was to determine that adults with growth hormone deficiency are predisposed towards greater cardiovascular mortality rates and insulin resistance. Earlier it was shown by us that short-duration treatments with low growth hormone dosages improved insulin sensitivity in young people. This current study was performed to explore the theory that a low growth hormone dose as compared to regular doses to normalize IGF-I levels can have altering effects on the sensitivity towards insulin, cardiovascular risk markings, body composition etc. [lipid profile, tumour necrosis factor-alpha (TNF-alpha), C-reactive protein (CRP), interleukin-6 (IL-6), and adiponectin] in adults with severe deficiency of growth hormones. Method of administration was during the one-year duration, 25 adults with deficiency in growth hormones were randomly selected to receive either a fixed dose or mean dose. Eight adults with deficient levels fo HGH and having matching BMI and age statistics acted as neutrals. Fasting samples of blood were collected at the baseline stage and at intervals of 1,3,6, 9 and 12 months. The analysis of sensitivity to insulin using technique of hyperinsulinaemic euglycaemic clamp as well as using X-ray absorptiometry with dual-energy techniques were conducted at the baseline and 12th month. The results of this experiment showed that fasting levels of glucose were decreased because of lowe growth hormone doses (P was less than 0.01) and there was greater sensitivity to insulin (P was less than 0.02). However, aspects like body composition, NEFA levels and risk markings pertaining to cardiovascular functions remained unchanged. Thus, the SGH did not alter insulin sensitivity but decreased the abdominal fat deposits (P was less than 0.05) the CRP (where P less than 0.05) and more NEFA levels (P less than 0.05) as well as IL-6 (P less than 0.05). There were no changes observed on analysis of neutral entities. The conclusion of this experiment is that as opposed to SGH, fixed low growth hormone administration increases sensitivity towards insulin without any changes in body composition, lipolysis or risk markings with cardiovascular functioning in adults having severe deficiency of growth hormones. Thus, Type 2 kinds of diabetes maybe reduced successfully by using fixed administration of low doses of growth hormones.
Effects of administration of sex steroids and/or growth hormones on protein turnover in body of older men and women.
By Blackman MR, Huang X, Herreman K, Harman SM, Pabst KM, Caballero B.
Performed at the Center for Human Nutrition at Johns Hopkins Bloomberg School of Public Health at Baltimore in Maryland.
Decreased activity of the growth hormone results in aging disorders, IGF-I resembling insulin-like growing as well as axes pertaining to sex steroids. There is also a decrease in protein synthesis as well as lean body mass. A placebo controlled operation with random and double-blind was used to study effects of administrating growth hormone for six months, only sex hormone (in women, the hormone replacement therapy while in men it was testosterone enanthate ) or the growth hormone as well as hormone replacement administration effects on synthesis of protein in 10 healthy men and 43 healthy women aged between 65 and 88 years. The administration of growth hormones showed improvement in IGF-I levels, much more in men. The administration of sex steroids enhanced estrogen levels in women and testosterone in men. The P was 0.05. Protein turnovers were calculated both prior to and after the treatment lasting 26 weeks. Constant and primed infusion of l-[1-(13)C]leucine was administered through this process. In men it was found that growth hormone as well as administration of T enhanced Leucine oxidation but did not change once the treatment was over. This was found in both men and women. In men it was found there were negligible levels of disposal of nonoxidative leucine in men and women because of the growth hormone administration. The changes in disposal of nonoxidative leucine were directly related to IGF-I level changes. Due to growth hormone and T treatments in men, the protein turnover enhanced significantly. These findings reveal that administering low doses of growth hormones in men and women enhanced synthesis of proteins. The coadministration of both testosterone as well as growth hormone increases such an effect in older men.
Effects of a two week administration of growth hormones on a 24 hour basis through indirect calorimetry in lean, healthy and young males.
By Hansen M, Larsson B, Morthorst R, Flyvbjerg A, Orskov H, Rasmussen MH, Kjaer M, Astrup A, Lange KH.
Performed at Institute of Sports Medicine at Copenhagen at Bispebjerg Hospital Building 8, Bispebjerg Bakke 23, DK-2400 Copenhagen NV, Denmark. Email: mh19@bbh.hosp.dk
The design of the current study was undertaken as a double-blind, randomized placebo controlled environment to determine the effects of administering growth hormones over a two week period and its effects on expenditure of energy as well as substrate oxidation in healthy males. A total of sixteen young men were separated into two sections. The study comprised measurements taken twice in 24 hours through indirect calorimetry, separated via a 2 week period with either growth hormone or Plc injections. When considering the baseline, there were no major changes noticed between both groups regarding hormonal, anthropometric, metabolic aspects and the parameters did not alter over this period in the Plc group. Administration of growth hormones resulted in increase of 4.4% increase in EE over 24 hours, as well as enhancement of fat oxidation by about 29%. The postabsorbtive phase showed a decline in respiratory quotients once an overnight fasting session was conducted. The lean body mass or LBM was increased only because of growth hormone administration. Thus, as conclusion, it can be inferred that growth hormone administration increases EE over a 24 hour period and this can be partially attributed to enhanced LBM. In addition, administration of growth hormone also stimulates combustion of fat, in the postabsorptive phase.
Age-related hormonal declines – whether there is a part growth hormone therapy plays in older men
By Di Somma C, Lombardi G, Colao A, Rota F.
Conducted by Department of Oncology, Clinical and Molecular Endocrinology at Federico II University through S Pansini at Napoli Italy. Email: gaelomba@unina.it
The reduction of somatotroph axis results in aging in people. This reduction has been the cause of catabolic sequences associated with aging. This in turn causes the IGF-I levels to decline at a rapid rate. This reflects the reduced secretion of growth hormones but it has also been found that reduction in secretion of the gonadal sex steroids and improper nutrition play a part too. The reduction of growth hormone secretions explain partially age-relevant disorders such as bones, metabolic rate, cardiovascular system, muscles, immunity, central nervous system and the general feeling of wellness. The regular aging as well as deficiency of growth hormones share many clinical symptoms and signs. However, the aging pattern associated with endocrine changes is distinct from changes in growth hormone levels or IGF-I levels in the body. This is a condition called hypopituitarism and there are many similarities associated between natural aging and deficiency of growth hormones. Older people have reduced growth hormone levels and this contributes to their frail constitution. It is yet to be clear if growth hormone administration can really reverse aging disorders or improve body function and structure. Many studies enrolling older subjects showed an increase of lean mass, better bone density and reduction in fat masses after administration of growth hormones. There has been no conclusive confirmation of this by the other studies conducted. Treatments using synthetic and natural secretagogues of growth hormones show a psychological pathway to restore normal secretions of IGF-I and growth hormones. Thus, as conclusion there is not enough evidence to show the therapeutic roles of IGF-I, rhGH or secretagogues in the aging process. More studies are required to elucidate the matter.
Are there gender-relevant effects because of growth hormone administration apparent on cardiac morphology, cardiovascular risk markings or atherosclerosis and performance? Here are results of a study over a period of 2 years in women and men with growth hormone deficiency.
By Colao A, Cuocolo A, Di Somma C, Acampa W, Spinelli L, Rota F, Spiezia S, Lombardi G, Savanelli MC.
Conducted at the department of Clinical and Molecular Endocrinology as well as Oncology at Federico II University of Naples in Italy. Email: colao@unina.it
The context of this study was that secretion of growth hormones and growth hormone replacement therapy are related to gender issues. The aim of the experiment was to study the effects of deficient growth hormones and GH replacement therapy on cardiovascular system, as per gender. The design was prospective and open. The experiment was performed at the hospital in a university. Subjects comprised 36 persons with severe growth hormone deficiency. These included 20 women and 18 men aged below 45 years. Thirty-six persons with matching BMI, gender and age who acted as controls. The dosage of growth hormone was at median dosage comprising 6.5 microg/Kg in men and around 7.7 microg/Kg in women for around 2 years. Measurements included C-reactive protein levels, fibrinogen, HDL cholesterol proportions, blood pressure, left VMI, heart rate, systolic function and diastolic filling. These were measured at both peak exercise and rest periods. The results showed that both men and women showed similar levels of insulin resistance, reduced cardiac function, lipid changes as well as IMT. Men showed more prevalence of diastolic dysfunction. Once growth hormone replacement therapy was administered IGF-I levels were normalized across all patients. The C-reactive protein level, lipid profile, fibrinogen etc. were also normalized. Total to HDL proportion was more in women as compared to men. The assessment index pertaining to homeostasis model was higher in the growth hormone deficient persons as compared to controls. It reduced only by 1.7% in men with the deficiency. The left VMI was normalized in both men and women during treatment and unusual diastolic function continued in three women while unusual systolic function continued in six women as well as one male. Both men and women showed decreased IMT and continued at a higher level compared to controls. The performance of exercised was normalized in all patients. The conclusion of this study showed that administration of growth hormones for a two-year period has benefits on the exercise performance and cardiovascular performance as well as atherosclerosis in men and women with growth hormone deficiency.
Joint actions of damaged pulse renewal of growth hormones in older men.
By Iranmanesh A, Vedhuis JD, Bowers CY.
Conducted by the Endocrine Research Unit, Department of Internal Medicine at the Mayo School of Graduate Medical Education, General Clinical Research Center at Mayo Clinic located at Rochester in Minnesota. Email: veldhuis.johannes@mayo.edu
The context of this study is that due to aging the bursts of growth hormone secretions reduce and hence this reduces the overall secretion of growth hormones. Various experimental research data shows that high amplitude of pulses of growth hormones are caused by reversible negative feedback inducing growth hormone cycles. It is yet unknown if aging hampers the autofeedback. The aim of this study is to establish if age attenuates as well as if IGF-I can potentiate negative feedback by using psychological pulses of growth hormones.
17 males of good health aged between 19 and 71 years were treated with infusion studies on different morning fasting in a university environment. Intravenous injections of pulse of salt water or rhGH to control negative feedback after which, in 2 hour interval, bolus of salt water was administered or the analog ghrelin. This would curtail feedback inhibition. The measurements of IGF-I levels and aging on autofeedback of growth hormones was performed using regression analysis. The results showed that the percentage of inhibition of feedback was in negative relation with age once growth hormone and saline infusions were administered and the overall IGF-I levels after the rhGH infusion was administered. However, as a sharp contrast, it was found that concentrations of sex steroids and the BMI were not related to a level of autoinhibition. The conclusion of this study is that a higher age in healthy males shows hampered growth hormone autofeedback. This can result in attenuated renewal in pulses of high amplitude of growth hormones. In contrast, higher levels of IGF-I in young males show more autoinhibition of growth hormones and this can result in prominent pulses of growth hormones.
Growth patterns resembling insulin-type growths I levels and the diagnosis of hormone deficiency in adults.
By Aimaretti G, Rovere S, Corneli G, Baldelli R, Granata R, Ghigo E, Grottoli S.
Conducted by Division of Metabolism and Endocrinology, in Department of Internal Medicine, conducted at University of Turin, Turin, Italy.
Within the context of appropriate clinical studies, current regulations state that diagnosis of growth hormone deficiency should be undertaken using biochemical and provocative testing. The measurement of growth resembling insulin-like pattern of growth as well as binding protein at three levels cannot all the time be used to differentiate between growth hormone deficient and healthy persons. In addition, it is to be noted that the IGFBP-3 marking for growth hormone status is not more sensitive than IGF-I and so there is a general consensus that this measurement cannot give useful information for diagnostics. The diagnostic values to measure IGF-I concentrations cannot rule out the deficiency of growth hormones in adults where the peak growth hormone responses to provocative testing is to be performed. Persons who are suspected to have deficiency of growth hormones and have unusually low IGF-I concentrations can be proper evidence of severe deficiency of growth hormones. This characteristic is applicable to persons who have had GHD since childhood. Persons with many hypopituitary defects obtained in their adult life will also qualify in this category. Usage of IGF-I concentrations to measure the sufficiency of growth hormone replacement therapy is accepted throughout.
Testosterone can curtail inhibition feedback of secretion of growth hormones because of artificially increased insulin-resembling growth-inducing I levels.
By Anderson SM, Veldhuis JD, Bowers CY, Iranmanesh A.
Conducted by the Endocrine Research Unit, at the Mayo School of Graduate Medical Education at the General Clinical Research Center, 200 First Street, Southwest, Mayo Clinic, Rochester, Minnesota. Email: veldhuis.johannes@mayo.edu
Current studies will test the theory that high doses of testosterone administration can induce growth hormone as well as IGF-I secretions. This is caused partially by curtailing the autonegative feedbacks caused by peptide by-products. To analyze this we used salt water or saline or IGF-I of human recombinant type, in 7 males of healthy status aged from 51 to 72 years. This was conducted after placebo administration and Testosterone in a random order. The growth hormone release was measured before fasting and after the GHRH injection. Analysis of statistics showed that when comparing Testosterone versus Placebo, it was found that there was a mean increase of growth hormones as well as IGF-I. Though these parameters increased, there was no change in growth hormone release induced by the GHRH injections. The second finding was that there was an increase in growth hormone nadir in the placebo controlled study as well as at the time of IGF-I infusions. The third analysis was that there was increased growth hormone release from the GHRH injection during the administration of IGF-I injection. The last inference was that it did not affect IGF-I parameters. Thus, in conclusion, higher doses of testosterone in older males increased dependant inhibition of IGF-I feedbacks as well as peak secretions of growth hormones. These effects of Testosterone are different from what was found in the study on postmenopausal women for estradiol. Thus, it can be inferred that estrogen as well as Testosterone change negative feedback for IGF-I differently.
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