Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We infused intravenously recombinant human Insulin-like Growth Factor-I (IGF-I; 1 microgram/kg/min for 120 minutes after an acute dose of 25 micrograms/kg) into chronically catheterized ovine fetuses (124-132 days gestation) to study its effect on the secretion of fetal ovine Growth Hormone (oGH). In all IGF-I infused fetuses, oGH concentrations fell during the infusion. The maximal change in the concentration of oGH (mean +/- SEM) was -54 +/- 10 ng/ml in contrast to +7 +/- 6 ng/ml in saline controls (p less than 0.005), a decrease of 33 +/- 4% (controls: +6 +/- 5%; p less than 0.005). By 60 minutes after the infusion of IGF-I was completed, the concentration of plasma oGH was comparable to control and pre-infusion values. In IGF-I infused fetuses, the mean concentration of insulin also decreased (p less than 0.02), whereas glucose levels remained unaltered. The results suggest that the lack of inhibitory feedback by the relatively low levels of circulating IGF-I is one factor in the hypersecretion of GH by the fetus.
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PMID:Hormone ontogeny in the ovine fetus: XXI. The effect of insulin-like growth factor-I on plasma fetal growth hormone, insulin and glucose concentrations. 328 98

In protein-calorie malnutrition, serum IGF-I concentrations are low despite high GH. This GH resistance might be due to a reduced number of liver GH binding sites as suggested by studies performed in fasted rats that were refed a low protein diet. To determine whether a postreceptor defect in GH action might also contribute to the GH resistance, we measured the number and the affinity constant of the liver GH binding sites and the serum IGF-I responses to injections of recombinant bGH in hypophysectomized female rats, fed a standard (15% protein) diet (N = 25) or a low (5%) protein diet (N = 25) for 8 days. There were no significant differences in the liver GH binding capacities between the 15% and the 5% protein-fed rats, whether expressed as pmol per liver (20.6 +/- 3.5 vs 14.4 +/- 1.3; mean +/- SEM; P less than 0.2; N = 5, respectively), pmol per mg DNA (1.08 +/- 0.16 vs 0.84 +/- 0.07; P less than 0.4) or fmol per mg of protein (28.98 +/- 5.04 vs 30.26 +/- 2.00; P greater than 0.5). Likewise, the affinity constants of the GH binding sites of the 15% and the 5% protein-fed rats were not significantly different (0.78 +/- 0.05 vs 0.78 +/- 0.07 x 10(9) l/mol; P greater than 0.5). Despite these non-significant reductions in liver GH binding sites, the IGF-I responses 24 h after sc injections of increasing doses of bovine GH were blunted in the rats fed the 5% protein diet.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Decreased serum insulin-like growth factor I response to growth hormone in hypophysectomized rats fed a low protein diet: evidence for a postreceptor defect. 338 36

Plasma insulin-like growth factor I concentrations from proportionate, chondrodystrophic and giant breeds were evaluated and compared with body size. IGF-I plasma concentrations were 91.2 +/- 10.9 micrograms/l in Keeshounds (proportionate dog), 122.6 +/- 25.4 micrograms/l in Bassethounds (chondrodystrophic dog) and 280 +/- 22.8 micrograms/l in German Shepherds (proportionate dog). The highest IGF-I level (389.6 +/- 24.2 micrograms/l) was found in the New Foundland, a giant breed (mean +/- SEM). The mean body weight was 11.8 +/- 0.4 kg in Keeshounds, 15.4 +/- 1.4 kg in Bassethounds, 32 +/- 1.5 kg in German Shepherds, and 45.6 +/- 1.7 kg in New Foundlands (mean +/- SEM). Body weight and plasma IGF-I concentration were significantly correlated (y (IGF-I) = -7.43 + 8.7 X (body weight); P less than 0.0001.
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PMID:Insulin-like growth factor I levels in proportionate dogs, chondrodystrophic dogs and in giant dogs. 338 43

Insulin and IGF-I affect in vitro ovarian stromal and follicular cell function in several species. We previously characterized insulin receptors on human granulosa cells obtained from in vitro fertilization procedures but were unable to demonstrate specific binding of IGF-I. Following modification of the assay conditions, we now report specific, high affinity IGF-1 binding sites on human granulosa cells. Substitution of equimolar concentrations of sucrose for sodium chloride in the buffer solution increased binding of IGF but not insulin in equilibrium assays. Maximal specific IGF-I binding was 2.69 +/- 0.30%/10(5) cells (SEM, n = 9) with half-maximal inhibition of binding at 2 ng/ml IGF-I. Unlabeled insulin recognized the type I IGF receptor with low affinity. An IGF-I receptor monoclonal antibody (alpha IR-3) inhibited 125I-IGF-I but not 125I-insulin binding. Affinity crosslinking followed by SDS/PAGE under reducing conditions revealed IGF-I binding at a molecular weight compatible with the alpha subunit of the type I IGF receptor and with a pattern of inhibition by various ligands that paralleled the equilibrium binding assays. IGF-I receptors are present on freshly isolated human ovarian granulosa cells obtained following pharmacologic stimulation with gonadotrophin according to the protocols of in vitro fertilization. The biologic function of these receptors currently is being investigated.
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PMID:Characterization of insulin-like growth factor binding to human granulosa cells obtained during in vitro fertilization. 345 Aug 73

We have studied the effect of a carbohydrate-restricted, calorie-reduced diet on the growth of young rats and on serum levels of GH, somatomedins [insulin-like growth factors (IGFs) I and II], total T4 and T3, free T4 index, and total corticosterone. Experimental animals consumed the same quantities of protein and fat as controls, but only 50.3% as much carbohydrate and 76% as many calories. While the experimental group grew at 69.4% of the control rate, their mean (+/- SEM) GH level (175.7 +/- 36.9 ng/mL) was not significantly different from that in the control group (180 +/- 30 ng/mL). In contrast, serum total IGF and IGF-I, while not correlated with serum GH levels, were significantly correlated in all animals with body weight (r = .87 and r = .82, respectively, P less than .01) and tail length (r = .61 and r = .62, respectively, P less than .01). The somatomedin levels of the carbohydrate-restricted rats were significantly lower than those of their age-matched, but not weight-matched, controls by the eighth day of study. Serum T4, T3, and free T4 index were not significantly different in these two groups, while total corticosterone in the experimental group (245 +/- 73 ng/mL) was slightly lower than in controls (292 +/- 80 ng/mL, P less than .05). These data indicate that by restricting carbohydrate intake we have compromised the anabolic use of dietary protein by growing rats, resulting in a retardation of growth and a reduction in serum total IGF and IGF-I levels.
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PMID:Effect of a carbohydrate-restricted, calorie-reduced diet on the growth of young rats and on serum growth hormone, somatomedins, total thyroxine and triiodothyronine, free T4 index, and total corticosterone. 360 Feb 92

The renal excretion of radioimmunoassayable somatomedin-C/insulin-like growth factor I (Sm-C/IGF-I) was measured in 12-h overnight urine samples obtained from 88 subjects, aged 3-19 yr. The participants included 34 healthy children (group 1), 29 children with idiopathic growth failure and normal GH stimulation tests (group 2), and 25 GH-deficient subjects (group 3). The mean (+/- SEM) urinary Sm-C/IGF-I excretion in group 1 (28.4 +/- 2.1 mU/kg) was significantly greater than that in group 2 (8.1 +/- 1.6 mU/kg) or group 3 (8.6 +/- 1.3 mU/kg). Twenty-two of the 29 subjects in group 2 had urinary Sm-C/IGF-I values less than 8 mU/kg. After the administration of biosynthetic GH to 12 GH-deficient subjects, urinary Sm-C/IGF-I excretion rose from 10.3 +/- 2.3 to 21.4 +/- 4.2 mU/kg within 12 h (P less than 0.05), indicating that renal excretion of Sm-C/IGF-I is GH dependent. One woman with acromegaly had markedly elevated urinary Sm-C/IGF-I excretion (420 mU/kg). The authenticity of urinary Sm-C/IGF-I was confirmed by high pressure liquid chromatography (HPLC). Assay of serial dilutions of urinary Sm-C/IGF-I demonstrated a direct proportionality between concentration and dilution. Although it is not possible to identify whether urinary Sm-C/IGF-I reflects local or generalized synthesis of the peptide, we hypothesize that quantitation of Sm-C/IGF-I in timed urine collections will yield additional information about GH production and action in children with normal and abnormal growth.
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PMID:Quantitation of urinary somatomedin-C in children with normal and abnormal growth. 368 Apr 79

In order to assess the potential relationship between human growth hormone (GH) and body composition (BC) and natural immunity (NI), we measured the effects of exogenous GH on fat weight (FW), fat-free weight (FFW), and the cytotoxic activity of natural killer (NK) cells in women with impaired GH secretion. Mean peak serum concentrations of GH in response to L-dopa/arginine stimulation were 6.2 +/- 1.1 (SEM) ng/mL in 6 untreated subjects (US) and 5.4 +/- 1.5 ng/mL in 6 GH-treated subjects (TS). Moreover, the pretreatment circulating levels of IGF-I were low in both groups (US 684 +/- 121 mU/mL and TS 583 +/- 83 mU/mL), and they correlated with pretest levels of NK cell activity (r = .59, P less than .05) when both groups were combined. The TS were given 700 micrograms of human GH IM for an average of 14 days while the US were studied in parallel without GH treatment. As measured by hydrodensitometry or skinfold anthropometry, FW decreased (26.1 +/- 6.8 kg to 23.8 +/- 6.3 kg, P less than .05) and FFW increased (44.9 +/- 3.3 kg to 46.2 +/- 3.8 kg, P less than .05) in the TS. In the US, there were no significant (P less than .05) changes in either FW or FFW. Using a standard 51Cr release assay to measure the specific lytic (SL) activity of NK cells, mean SL activity increased from 24.4 +/- 7.0% to 44.1 +/- 8.9% (P less than .05) in the TS, whereas levels in the US were not altered significantly (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Exogenous growth hormone treatment alters body composition and increases natural killer cell activity in women with impaired endogenous growth hormone secretion. 368 83

Determination of plasma IGF-I concentrations is not easily accessible to clinical use at present because of extremely limited supply of purified natural IGF-I essential for its assay system. Thus, an alternative method has recently been introduced by the development of a specific radioimmunoassay (RIA) for IGF-I (26-46). We examined the specificity and sensitivity of this assay system, and then investigated the changes in plasma concentrations of IGF-I in normal children, adults and in patients with various endocrine and metabolic diseases. Each plasma sample was subjected to acid-ethanol treatment before assay to separate IGF-I from its binding protein. The recovery rate of known amount of IGF-I (26-46) added to untreated plasma sample was more than 90%. The coefficients of variation of intra- and interassay were 9.0% and 13.6%, respectively. This assay system was able to detect IGF-I as low as 10 pg/tube. When plasma sample of a patient with active acromegaly was applied to Sephadex G-75 column, immunoreactive IGF-I was eluted at the position of 7,000 molecular weight. An inhibition curve of plasma extract from an acromegalic patient was parallel to that of IGF-I (26-46), indicating that the RIA could detect IGF-I. There was no remarkable difference between IGF-I values of plasma and serum from the same individual. The value of IGF-I concentration of cord plasma was considerably low (144 +/- 6.7 pg/ml, M +/- SEM) as compared with that of sera of 49 normal children aged 7-12 12 years (320 +/- 14.3 pg/ml). The highest value (460 +/- 54 pg/ml) was attained at the age of 13 years, followed by gradual decrease toward adult age. Plasma IGF-I concentration of normal adults between 20 and 69 years of age was 290 +/- 10 pg/ml. When plasma IGF-I values of adult males and females were separately plotted against age group of each decade, the value declined gradually with age in males while in females there was a remarkable increase in plasma IGF-I concentration at 4th and 5th decades, suggesting the effect of hormonal change at menopause on plasma IGF-I levels. There was a good correlation between disorders of GH secretion and plasma IGF-I concentrations. In 10 cases of active acromegaly the level was 506 +/- 67 pg/ml (285-970 pg/ml). On the other hand in 20 patients with pituitary dwarfism it was only 180 +/- 15 pg/ml.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Studies on plasma insulin-like growth factor (IGF)-I levels in normal subjects and in patients with various endocrine and metabolic diseases using radioimmunoassay for synthetic IGF-I (26-46)]. 369 96

We have studied the effect of a lysine-deficient diet on the growth of young rats and on serum levels of GH, somatomedins [insulin-like growth factors (IGFs) I and II], insulin, total T4 and T3, free T4 index, and total corticosterone. Rats eating a wheat gluten diet consumed about one third as much lysine as controls eating an isocaloric and isonitrogenous casein diet and grew at approximately 56% of the control rate. The mean (+/- SEM) GH level in the experimental group (68 +/- 9 ng/ml) was significantly lower (P less than 0.01) than that in the controls (106 +/- 17 ng/ml), but was not correlated with age or body weight and was only weakly correlated with total IGF. In contrast, total IGF and IGF-I were significantly correlated with age and body weight (r = 0.86 and r = 0.84, respectively; P less than 0.01). The levels of these somatomedins in the wheat gluten-fed animals were consistently and significantly lower than those in their age-matched controls, but not significantly different from those in their weight-matched controls, throughout the study. Serum total T4 and T3 (but not the free T4 index) and corticosterone were significantly elevated in the experimental rats, perhaps representing a serum binding globulin adaptation to lysine deficiency that is not clearly understood. In this study, we have compromised the ability of growing rats to use dietary protein anabolically to examine the nutritional effects of qualitative protein deficiency on growth and the growth-promoting endocrine system.
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PMID:Protein utilization in growth: effect of lysine deficiency on serum growth hormone, somatomedins, insulin, total thyroxine (T4) and triiodothyronine, free T4 index, and total corticosterone. 392 59

We have studied the effect of a calorie-restricted diet on the growth of young rats and on serum levels of GH, somatomedins (insulin-like growth factors I and II), total T4 and T3, free T4 index, and total corticosterone. Experimental rats consumed the same quantities of protein and carbohydrate as control animals, but less fat, so that their calorie intake was approximately 76% that of controls. The mean (+/- SEM) GH level in the experimental group (78 +/- 21 ng/ml) was not significantly different from that in the control group (89 +/- 31 ng/ml). In contrast, serum total insulin-like growth factor and insulin-like growth factor IGF-I, while not correlated with serum GH, were significantly correlated with age and body weight (r = 0.93 and r = 0.69, respectively; P less than 0.01). The levels of these somatomedins in the calorie-restricted rats were significantly lower than those in their age-matched, but not weight-matched, controls after approximately 2 weeks of study. Serum T4, T3, and free T4 index were all significantly reduced in the experimental animals and may represent an adaptive response to calorie restriction. Serum corticosterone levels in the experimental and control rats were essentially identical. In this study, by restricting calorie intake we have compromised the ability of growing rats to use dietary protein anabolically, creating a useful model to examine in some detail nutritional influences on growth and the growth-promoting endocrine system.
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PMID:Protein utilization in growth: effect of calorie deficiency on serum growth hormone, somatomedins, total thyroxine (T4) and triiodothyronine, free T4 index, and total corticosterone. 406 34


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