Human Growth Hormone Levels Research Articles

Serum Levels of 20-Kilodalton Human Growth Hormone (GH) in Children with Simple Obesity

Twenty-kilodalton human GH, a human GH (hGH) variant, has insulin-like and anti-insulin-like actions different from 22-kilodalton hGH (22K). The diabetogenic action of twenty-kilodalton hGH (20K) is reported to be weaker than that of 22K, yet it is still unclear whether secretion of 20K is influenced by factors in carbohydrate metabolism. We measured serum 20K and 22K in children with simple obesity and studied the regulation of 20K production. The subject were 124 boys (9.78 ± 1.94 yr old, body mass index (BMI) 25.88 ± 2.43 kg/m2) and 54 girls (10.29 ± 2.25 yr old, BMI 26.90 ± 3.72 kg/m2) with simple obesity. The serum samples were taken after overnight fasting. The data was compared with the data from children with non-GH deficient (GHD) short stature. The mean serum concentrations of 22K and 20K were 1.47 ± 1.63 ng/ml and 81.3 ± 80.3 pg/ml in obese boys and 1.86 ± 2.00 ng/ml and 108.9 ± 120.4 pg/ml in obese girls. The percentage of 20K in hGH was 7.4 ± 5.0% in obese boys and 6.5 ± 2.9% in obese girls, and the percentage was not significantly different from the percentage of 20K in children with non-GHD short stature. The height SD score, obesity index, body fat mass, BMI, fasting blood sugar, insulin, homeostasis model assessment-R (HOMA-R), HbA1c, total cholesterol, triglyceride, leptin and IGFBP-1 were not correlated to the percentage of 20K. We conclude that the percentage of 20K is constant not only in normal children but also in obese children, and factors that correlate with obesity such as glucose and insulin do not influence the 20K splicing mechanism.

Serum levels of human growth hormone during different penile conditions in the cavernous and systemic blood of healthy men and patients with erectile dysfunction

Objectives. To detect changes in growth hormone (GH) serum levels during different penile conditions in the cavernous and systemic blood of patients with erectile dysfunction and compare them with the course of GH registered in healthy men. It has been suggested that human GH is involved in sexual maturation and plays a regulatory role in male reproductive function. Deficiency may result in fatigability, loss of sexual desire and erection, or oligospermia or azoospermia. It is assumed that the biologic effects of GH include insulin-like growth factor 1-mediated stimulation of endothelial nitric oxide formation. It has recently been demonstrated that GH serum levels in the systemic and cavernous blood of healthy men increases during developing penile erection. Methods. Thirty-five healthy adult men and 45 patients with erectile dysfunction of either organogenic or psychogenic etiology were exposed to visual and tactile erotic stimuli to elicit penile tumescence and, in the group of healthy subjects, rigidity. Whole blood was simultaneously aspirated from the corpus cavernosum and the cubital vein during the different functional conditions of the penis. Serum levels of GH were determined by means of an immunoradiometric assay. Results. In the healthy subjects, systemic GH serum levels significantly increased during penile tumescence, followed by a transient decline from tumescence to rigidity and detumescence. In the unselected patients, the mean GH levels during penile flaccidity were determined to be about sevenfold lower than those registered in the blood of the healthy men. During penile tumescence, the mean increase in the GH levels in the systemic and cavernous blood of psychogenic patients was comparable to that seen in healthy men, but, in the group of organogenic patients, this increase was found to be negligible. Conclusions. We believe our data provide strong evidence that GH may be of major importance in the maintenance of male erectile capability—probably through a stimulating effect on cyclic guanosine monophosphate generation in human cavernous smooth muscle—and that a decline in GH release may contribute to the manifestation of erectile dysfunction.

Human placental growth hormone causes severe insulin resistance in transgenic mice

OBJECTIVE: The insulin resistance of pregnancy is considered to be mediated by human placental lactogen, but the metabolic effects of human placental growth hormone have not been well defined. Our aim was to evaluate the effect of placental growth hormone on insulin sensitivity in vivo using transgenic mice that overexpress the human placental growth hormone gene. STUDY DESIGN: Glucose and insulin tolerance tests were performed on 5 transgenic mice that overexpressed the human placental growth hormone variant gene and 6 normal littermate controls. The body composition of the mice was assessed by dual-energy radiograph absorptiometry, and free fatty acid levels were measured as a marker of lipolysis. RESULTS: The human placental growth hormone levels in the transgenic mice were comparable to those attained in the third trimester of pregnancy. These mice were nearly twice as heavy as the control mice, and their body composition differed by a significant increase in bone density and a small decrease in percentage of body fat. Fasting insulin levels in the transgenic mice that overexpressed placental growth hormone were approximately 4-fold higher than the control mice (1.57 ± 0.22 ng/mL vs 0.38 ± 0.07 ng/mL; P <.001) and 7 times higher 30 minutes after glucose stimulation (4.17 ± 0.54 ng/mL vs 0.62 ± 0.10 ng/mL; P <.0001) with no significant difference in either fasting or postchallenge glucose levels. Insulin sensitivity was markedly decreased in the transgenic mice, as demonstrated by an insignificant decline in glucose levels after insulin injection compared with the control mice, which demonstrated more than a 65% reduction in glucose levels (P <.001). CONCLUSION: Human placental growth hormone causes insulin resistance as manifested by fasting and postprandial hyperinsulinemia and minimal glucose lowering in response to insulin injection. Human placental growth hormone is a highly likely candidate to mediate the insulin resistance of pregnancy. (Am J Obstet Gynecol 2002;186:512-7.)

Effects of Sleep and Sleep Deprivation on Interleukin-6, Growth Hormone, Cortisol, and Melatonin Levels in Humans

Effects of Sleep and Sleep Deprivation on Interleukin-6, Growth Hormone, Cortisol, and Melatonin Levels in Humans

Dose-dependence of bacterial lipopolysaccharide (LPS) effects on peak response and time course of the immune-endocrine host response in humans.

Dose-dependence of lipopolysaccharide (LPS) effects on peak and time course parameters of the immune-endocrine host response was examined in a placebo-controlled design. Data from 42 male volunteers were included. 0.4 or 0.8 ng LPS/kg body weight were applied at 7.00 p.m. Body temperature, heart rate and leukocyte counts were quantified. Plasma levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), adrenocorticotropic hormone (ACTH), cortisol and human growth hormone (hGH) were measured. LPS increased significantly the levels of immune (TNF-alpha, IL-6) and endocrine (ACTH, cortisol) parameters. HGH secretion was advanced without changes in the total amount of hGH released. Dose-dependence of endotoxin's effects was significant for neuroendocrine (cortisol) and physiological (temperature, heart rate) parameters. Examination of time course parameters demonstrated that the higher dose of endotoxin prolonged the increases in temperature, IL-6 and cortisol levels. Our data show that increases in the dosage of LPS lead to differential peak responses and changed time course patterns of the human host response.

Adenovirus-mediated regulable target gene expression in vivo.

To regulate expression of a transferred gene in response to an exogenous compound, we have combined a high capacity adenoviral vector devoid of all viral coding sequences with a regulatory system that can be used to express a target gene in vivo in a selected site and at a desired time. This system uses a chimeric transactivator, GLp65, which consists of a mutated progesterone receptor-ligand binding domain fused to the GAL4 DNA binding domain and part of the activation domain of the human p65 protein, a component of the NF-kappaB complex. In the presence of the antiprogestin mifepristone, this chimeric regulator binds to a target gene containing the 17-mer GAL4 binding site, resulting in an efficient ligand-inducible transactivation of the target gene. We inserted the regulator GLp65 and a regulable human growth hormone target gene containing the 17-mer GAL4 binding site into the same adenoviral vector. To obtain tissue-specific expression of the target gene, we coupled the regulator to a liver-specific promoter. Infection of HepG2 cells and experimental mice with the adenovirus resulted in consistently high induction levels of human growth hormone in the presence of mifepristone whereas the transgene expression was undetectable in the absence of the ligand. Taken together, our regulable adenoviral vector represents an important tool for transgene regulation that can be used for potentially diverse applications, ranging from tissue-specific gene expression in transgenic animals to human gene therapy.

Serum levels of 20-kilodalton human growth hormone (GH) are parallel those of 22-kilodalton human GH in normal and short children.

Twenty-kilodalton human GH (20K), which is one of the human GH (hGH) variants, is thought to be produced by alternative premessenger ribonucleic acid splicing. However, its physiological role is still unclear due to the lack of a specific assay. We have measured serum 20K and 22-kDa hGH (22K) by specific ELISAs to investigate the physiological role of 20K in children. The subjects were 162 normal children, aged 1 month to 20 yr; 12 patients with GH deficiency (GHD), aged 11 months to 13 yr; 57 children with non-GHD short stature, aged 2-17 yr; and 13 girls with Turner's syndrome, aged 5 months to 15 yr. Samples were collected at random from normal children and were collected after hGH provocative tests and 3-h nocturnal sleep from GHD, non-GHD short stature, and Turner's syndrome children. The mean basal serum concentrations of 22K and 20K were 2.4 +/- 2.8 ng/mL and 152.3 +/- 184.0 pg/mL in normal boys and 2.5 +/- 3.1 ng/mL and 130.6 +/- 171.5 pg/mL in normal girls, respectively. The percentages of 20K (%20K) were 5.8 +/- 2.1% and 6.0 +/- 3.2% in 83 normal boys and 79 normal girls, respectively. There was no significant difference in %20K either among ages or between the prepubertal stage and the pubertal stage in normal boys and girls. The mean %20K values in basal samples of provocative tests in 12 patients with GHD, non-GHD short stature, and Turner's syndrome were 6.5 +/- 2.4%, 6.5 +/- 3.8%, and 5.9 +/- 3.2%, respectively. There was no significant difference in %20K among normal children and these growth disorders, and there was no significant difference in %20K throughout the hGH provocative tests and 3-h nocturnal sleep in these growth disorders. There was also no significant correlation between the percentage of 20K and the height SD score or body mass index in either normal children or subjects with these growth disorders. In conclusion, the %20K is constant, regardless of age, sex, puberty, height SD score, body mass index, and GH secretion status. The regulation of serum 20K levels remains to be established.

Maternal Serum Placental Growth Hormone and Insulinlike Growth Factor Binding Proteins 1 and 3 in Pregnancies Affected by Fetal Aneuploidy and Other Abnormalities: Implications for Prenatal Diagnosis of Trisomy 21

In the present study, we determined circulating serum levels of human placental growth hormone (hPGH) and insulinlike growth factor binding proteins 1 and 3 (IGFBP-1 and IGFBP-3) using two-site radioimmunoassays during the gestational midtrimester of pregnancies affected by chromosomal disorders with the aim of identifying potential marker substances that might have a significant discriminative and predictive value for prenatal diagnosis of fetal chromosomal aberrations and of organ malformations such as neural-tube defect. Our results show that the maternal serum levels of hPGH were significantly elevated in pregnancies affected by chromosomal anomalies or organ malformations as compared with controls. The distribution of IGFBP-1 concentrations for all experimental groups except trisomy 21 were closely similar to the normal population. IGFBP-3 decreased slightly in pregnancies affected by Down syndrome. These findings suggest that hPGH may be useful as an additional marker in prenatal screening for Down syndrome.

Biodistribution and gene expression of lipid/plasmid complexes after systemic administration.

The objectives of this study were to investigate the influence of physicochemical properties of lipid/plasmid complexes on in vivo gene transfer and biodistribution characteristics. Formulations based on 1,2-di-O-octadecenyl-3-trimethylammonium propane (DOTMA) and novel biodegradable cationic lipids, such as ethyl dioleoyl phosphatidylcholine (EDOPC), ethyl palmitoyl myristyl phosphatidylcholine (EPMPC), myristyl myristoyl carnitine ester (MMCE), and oleyl oleoyl L-carnitine ester (DOLCE), were assessed for gene expression after tail vein injection of lipid/plasmid complexes in mice. Gene expression was influenced by cationic lipid structure, cationic lipid-to-colipid molar ratios, plasmid-to-lipid charge ratios, and precondensation liposome size. Detectable levels of human growth hormone (hGH) in serum, human factor IX (hFIX) in plasma, and chloramphenicol acetyltransferase (CAT) in the lung and liver were observed with positively charged lipid/plasmid complexes prepared from 400-nm extruded liposomes with a cationic lipid-to-colipid ratio of 4:1 (mol/mol). Intravenous administration of lipid/CAT plasmid complexes resulted in distribution of plasmid DNA mainly to the lung at 15 min after injection. Plasmid DNA accumulation in the liver increased with time up to 24 hr postinjection. There was a 10-fold decrease in the amount of plasmid DNA in the lung at 15 min after injection, when the lipid/plasmid complex charge ratio was decreased from 3:1 to 0.5:1 (+/-). Bright fluorescent aggregates were evident in in vivo-transfected lung with the positively charged pCMV-CAT/DOLCE:dioleyl phosphatidylethanolamine (DOPE) (1:1, mol/mol) complexes, while more discrete punctate fluorescence was observed with a 4:1 molar ratio of cationic lipid:colipid formulations. Preinjection of polyanions such as plasmid, dextran sulfate, polycytidic acid, and polyinosinic acid decreased hGH expression, whereas the preinjection of both positively charged and neutral liposomes had no effect on hGH serum levels. Of the cationic lipids tested, DOLCE was found to be the most effective potentially biodegradable cationic lipid. A correlation between gene expression and cationic lipid:colipid ratios and lipid-to-plasmid charge ratio was also observed for DOTMA- and DOLCE-based formulations.

In vivo modulation by glucose of human placental growth hormone level in the maternal circulation

The growth hormone (GH)-enhancing monoclonal antibody (MAb) OA15 defines a functionally linear epitope (residues 91–102) lying on the loop connecting helices 2 and 3 of the bovine GH (bGH) molecule. Further studies revealed that a number of analogue peptides were possible by substituting residues within the epitope peptide. The aim of this study was examine the ability of antisera prepared against these peptides to mimic the ability of MAb OA15 to enhance bGH and porcine GH (pGH) activity. Antisera against the epitope peptide and its analogues were characterised by their ability to bind to bGH by solid-phase ELISA and liquid phase RIA. Antisera binding [125I]-bGH enhanced the somatogenic activity of both exogenous bGH and pGH as determined by the incorporation of 35SO42− into the costal cartilage of Snell dwarf mice. Long term treatment of Snell dwarf mice with GH complexed to anti-peptide F (QFLSRITNSLV) antisera stimulated mice to reach their normal mature weight significantly faster than that of mice treated with GH alone, although the final weight of the animal was not altered. This finding suggests that enhancement takes place via normal physiological processes and that antibody-mediated enhancement of GH action may have a potential application in manipulating growth in the livestock industry.

Suppression of immunological response against a transgene product delivered from microencapsulated cells.

A potential obstacle to successful gene therapy for some patients is the in vivo production of neutralizing antibodies against the recombinant therapeutic product delivered. To mimic this clinical situation, we implanted microencapsulated recombinant cells producing human growth hormone into C57B1/6 mice to provoke antihuman growth hormone antibody production. We then investigated the efficacy of different immunosuppressive treatments to inhibit the development of neutralizing antibodies. The experimental mice were treated with either an immunosuppressive drug (FK506 or cyclophosphamide), a cytokine (interferon-gamma [IFN-gamma] or interleukin-12 [IL-12], or a monoclonal antibody (anti-CD4, anti-gp39, or CTLA4-Ig). Serum human growth hormone and mouse anti-human growth hormone antibody levels were measured by enzyme-linked immunosorbent assay (ELISA) for 4 weeks. There were three patterns of response noted among the seven treatment groups. First, the mice receiving IFN-gamma, IL-12, anti-gp39, or CTLA4-Ig were similar to the untreated controls-no suppression of anti-hGH antibodies and no improvement in delivery of hGH. Next, the mice receiving FK506 or cyclosphosphamide showed > or = 90% suppression of antibodies but also no improvement in product delivery. Last, the mice receiving anti-CD4 showed almost complete antibody suppression over 1 month postimplantation. Furthermore, only anti-CD4 permitted a sustained level of human growth hormone delivery to day 28, in contrast to the controls whose human growth hormone delivery was undetectable by day 14 postimplantation. Hence, the use of anti-CD4 inhibited formation of neutralizing antibodies against a recombinant gene product delivered in vivo, and allowed prolonged delivery of a foreign protein. Its role as adjunct treatment for appropriate patients receiving gene therapy should be examined further.

Peripheral plasma levels of human growth hormone releasing hormone (GHRH) during the sleep test in short children.

Peripheral plasma levels of human growth hormone releasing hormone (GHRH) during the sleep test in short children.

STRENGTH, FIBER TYPE, AND HORMONAL RESPONSES IN THE ELDERLY WITH PROGRESSIVE RESISTANCE EXERCISE 1453

The purpose of this study was to determine the effects of 24-weeks of progressive resistance exercise training on strength, fiber type cross-sectional area (CSA), plasma levels of human growth hormone (hGH) and insulin-like growth factor I (IGF-I) in elderly males and females. Subjects, ages 65-90 years (79.2 ± 6.9 yrs) were randomly placed in a control group, (n=5, performed walking), and an experimental group (n=15, performed 12 exercises, 3 days per week with predominantly free weights). The training protocol emphasized total body strength and power (e.g. squats and bench press) and utilized 4 sets of 4 repetitions at 40% of 1 repetition maximum(1RM) proceeding to 3 sets of 3 repetitions at 80% 1RM over 24 weeks. Baseline(at rest) plasma samples were taken before (week 0), during (week 12), after(week 25) 24 weeks of training. Muscle CSA was analyzed from the needle biopsy technique and histochemically stained for myosin ATPase. There was a significant decrease of 9% in strength (25.08± 1.94 kg to 22.71± 1.75 kg), a significant decrease of 16% in type II fiber CSA(1977.41±288.71 to 1704.90±88.0) and a decrease of 10% in type I fiber CSA (6020.43±813.97 μm2 to 5397.69±1092.70) in the control group. There was a significant strength increase of 31%(23.86± 1.39 kg to 34.30± 1.79 kg), a significant type II fiber CSA increase of 31% (2097.57± 213.07μm2 to 2743.98± 314.51μm2), and no significant difference in type I CSA in the experimental group. There was no significant difference in plasma levels of hGH between groups. However, a trend (p= 0.07) for the increased IGF-I concentrations was observed (136.84± 29.90 ng/ml to 170.98± 37.11 ng/ml) in the experimental group. These results suggest that the significant increase in strength observed in the experimental group may be due, in part, to the hypertrophy of type II fiber CSA which may influence the increasing concentrations of IGF-I.

A Comparison of Resting Metabolic Rate, Self-Rated Food Intake, Growth Hormone, and Insulin Levels in Obese and Nonobese Preadolescents

LAESSLE, R. G., H. WURMSER AND K. M. PIRKE. A comparison of resting metabolic rate, self-rated food intake, growth hormone, and insulin levels in obese and nonobese preadolescents. PHYSIOL BEHAV 61(5) 725–729, 1997.—The objective was to investigate metabolic (resting metabolic rate), behavioral (energy intake), and endocrine variables (fasting insulin and growth hormone levels) potentially responsible for a positive energy balance in obese children in a cross-sectional study. The study was in 25 obese children aged 8 to 12 years and 21 nonobese children of the same age range. Weight, height, lean body mass (LBM) and fatmass (FM) were measured by bioelectrical impedance analysis, resting metabolic rate (indirect calorimetry) for the duration of 25 min, 7-day food records and fasting levels of insulin and human growth hormone (HGH). In the total sample, no differences were found in resting metabolic rate (RMR controlled for differences in weight) and energy intake between groups, whereas fasting insulin level was significantly higher and basal growth hormone concentration was significantly lower in the obese children. In RMR, there were significant age-dependent differences only in 10-year-old children, with the obese subjects showing lower values. The results fit in a multidimensional model, taking into account a critical period in prepubertal age for the development of childhood obesity. This period may be characterized by a reduced RMR, which results in an increased body weight, even if there is no excessive energy intake.

Different female reproductive phenotypes determined by human growth hormone (hGH) levels in hGH-transgenic rats.

The effect of continuous human GH (hGH) secretion on female reproduction was studied in adult female transgenic rats expressing the hGH gene with a mouse whey acidic protein (mWAP) promoter. Two lines of transgenic female rats carrying the mWAP/hGH gene were established and used in the study. One was characterized by relatively high levels of serum hGH (high line), and the other had relatively low levels (low line). High-line female rats had recurring, pseudopregnancy-like estrous cycles accompanied by increased serum progesterone levels for 2 wk after ovulation, and they were fertile. In these rats, luteinization occurred spontaneously without cervical stimulation, probably due to high levels of serum hGH, which has prolactin (PRL)-like activity in the rat. Although low-line female rats had recurring, regular 4-day estrous cycles, they were sterile. In these rats, pseudopregnancy could not be induced by mating or by mechanical cervical stimulation. PRL surges following cervical stimulation were not detected, and PRL secretion was not induced by a dopamine antagonist, metoclopramide. The ovarian tissue in this line had a much higher number of corpora lutea and grew much heavier than in normal littermates, suggesting impairment of PRL-induced structural luteolysis. Suppression of PRL secretion in low-line rats was, at least in part, due to a marked decrease in the number of lactotrophs in the pituitary. The present study shows that the serum hGH level plays a crucial role in regulating luteal function in female transgenic rats expressing the hGH gene.

Systemic delivery of human growth hormone or human factor IX in dogs by reintroduced genetically modified autologous bone marrow stromal cells.

Canine bone marrow stromal cells were expanded to numbers in excess of 10(9) cells from the initial 10-20 ml of marrow aspirates and transfected to express high levels of human growth hormone (hGH) in vitro. Ex vivo-modified marrow stromal cells were used in a gene therapy model system for the systemic delivery of transgene products in dogs. Adherent bone marrow stromal cell cultures, established and expanded from iliac crest marrow aspirates from each of 8 dogs, were transfected with a hGH gene plasmid expression vector and shown to express from 0.54-3.84 micrograms/10(6) cells per 24 hr hGH in vitro. The transfected plasmid vector does not possess a eukaryotic origin of replication nor does it possess sequences required for efficient integration into the host cell genome. As such, expression was expected to be transient. Transfected cells were autologously reintroduced into each dog by either infusion into a foreleg vein or directly into iliac crest marrow. In two cases, the stromal cells were cryopreserved following transfection, and subsequently thawed and infused. In one case, the expanded stromal cells were first cryopreserved, and then thawed, recultured, transfected, and infused. Reintroduced cell numbers ranged from 2.2 x 10(7) to 2.6 x 10(9), with total hGH expression capacities ranging from 62 to 1,400 micrograms/24 hr. Plasma of each of the dogs contained detectable hGH for a mean of 3.1 days (SD +/- 0.8 day) ranging from 2 to 5 days following reinfusion of cells. Peak plasma levels ranged from 0.10 to 1.76 ng/ml. Similar hGH expression values, based upon total expression capacity of the cells infused and dog body weight, were obtained for all dogs. Vector-modified stromal cells were detectable, by polymerase chain reaction (PCR) analysis, in the peripheral circulation following reinfusion in all 4 dogs analyzed. In 3 of the dogs, modified stromal cells were detected for 8.5-15 weeks. In addition, modified stromal cells were detected in iliac crest marrow of 2 dogs for 9 and 13 weeks, respectively, following reinfusion. In another experiment, cultured bone marrow stromal cells were transfected with a human factor IX (hFIX) plasmid vector. Modified cells (5.57 x 10(8)), with a total hFIX expression capacity of 281 micrograms/24 hr, were reinfused, resulting in detectable hFIX in plasma continuously for 9 days with a peak level of 8 ng/ml on day 1. These results demonstrate that the ex vivo bone marrow stromal cell system is a potentially powerful method by which to deliver secreted transgene product to the systemic circulation of large animals.

Tissue-engineered skeletal muscle organoids for reversible gene therapy.

Genetically modified murine skeletal myoblasts were tissue engineered in vitro into organ-like structures (organoids) containing only postmitotic myofibers secreting pharmacological levels of recombinant human growth hormone (rhGH). Subcutaneous organoid implantation under tension led to the rapid and stable appearance of physiological sera levels of rhGH for up to 12 weeks, whereas surgical removal led to its rapid disappearance. Reversible delivery of bioactive compounds from postmitotic cells in tissue engineered organs has several advantages over other forms of muscle gene therapy.

Oral drug turns on gene transcription

Researchers at a biotech firm have for the first time used rapamycin, an oral drug, to control production of a therapeutic protein by engineered human cells in mice. Rapamycin acts as a dimerizer to link two other proteins made by the engineered cells. When bound together, the two proteins form an active transcription factor that induces the cells to express sustained and therapeutic levels of human growth hormone (hGH). Scientific director Michael Gilman and coworkers at Ariad Gene Therapeutics, Cambridge, Mass., controlled hGH production with rapamycin in a dosedependent manner in mice implanted with engineered cells containing the hGH gene and two regulatory genes for transcription factor proteins [Nature Medicine, 2,1028 (1996)]. The two regulatory proteins had been modified to include recognition sites for rapamycin. When rapamycin was given to the mice, the two proteins were spliced together in the engineered cells—forming a complex that bound to the cells' DNA, activated the hGH gene, and ...

A humanized system for pharmacologic control of gene expression.

Gene therapy was originally conceived as a medical intervention to replace or correct defective genes in patients with inherited disorders. However, it may have much broader potential as an alternative delivery platform for protein therapeutics, such as cytokines, hormones, antibodies and novel engineered proteins. One key technical barrier to the widespread implementation of this form of therapy is the need for precise control over the level of protein production. A suitable system for pharmacologic control of therapeutic gene expression would permit precise titration of gene product dosage, intermittent or pulsatile treatment, and ready termination of therapy by withdrawal of the activating drug. We set out to design such a system with the following properties: (1) low baseline expression and high induction ratio; (2) positive control by an orally bioavailable small-molecule drug; (3) reduced potential for immune recognition through the exclusive use of human proteins; and (4) modularity to allow the independent optimization of each component using the tools of protein engineering. We report here the properties of this system and demonstrate its use to control circulating levels of human growth hormone in mice implanted with engineered human cells.

Transnasal stereotactic surgery of pituitary adenomas concomitant with acromegaly.

Since 1960 we have performed stereotactic transsphenoidal cryohypophysectomy in 70 patients with pituitary adenomas, 42 women and 28 men, aged 11-59 years. The dominant clinical syndrome was acromegaly in 50 patients, galactorrhea in 9, amenorrhea in 5, adiposogenital dystrophy in 4 and gigantism with mild endocrine symptomatology in 2 patients. In 67 patients the histological structure of the tumor was established by biopsy (50 patients with eosinophil adenoma, 10 with mixed-type adenoma, 4 with chromophobe adenoma and 3 with basophil adenoma). Somatotropic hormone, human growth hormone, prolactin, ACTH and 17-ketosteroid levels indicated active/inactive adenomas. In 42 cases the adenoma was only intrasellar, which was confirmed by contrast X-ray investigations, CT scanning, angiography and ophthalmological investigation. Transnasal stereotactic cryohypophysectomy was performed in all 70 cases using a stereotactic apparatus especially designed for operations on the pituitary. All patients (except 2) tolerated the operation well. No complications occurred. Vision deteriorated after operation in 1 patient. Thrombosis of the left middle cerebral artery developed in another patient. All the other patients noted improvement directly after operation - rapid diminution of signs of acromegaly and rapid restoration of normal values in hormonal tests. Six patients with continuing growth of the tumor underwent a second operation 1.5-6 years after the first operation. We conclude from our own clinical experience and information from the literature that transnasal stereotactic cryodestruction is highly effective and relatively safe in the management of pituitary adenoma.