UNIPROT:P61278 - FACTA Search

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Query: UNIPROT:P61278 (somatostatin)
22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ability of TSH to stimulate synthesis and release of thyroid hormones in ovine thyroid follicles in vitro depends partially on a synergy with insulin-like growth factors (IGFs). The cellular availability of IGFs may be influenced by the release of several IGF binding proteins (IGFBPs). The purposes of these studies was to 1) further characterize the species of IGFBPs synthesized by thyroid follicles, 2) examine the ability of TSH and cortisol to alter IGFBP gene expression and protein release, and 3) investigate the actions of exogenous IGFBPs on thyroid cell function. Adult sheep thyroid follicles were isolated after collagenase digestion, grown to confluence in Coon's modified Ham's F12M medium (OH) with the addition of transferrin, glycylhistidyl-lysine, somatostatin (3H), cortisol and insulin, and maintained in serum-free test media with or without further supplements for up to 48 h. Conditioned media were analyzed for IGFBP presence by Western ligand blotting, and by immunoblotting using specific antisera against bovine IGFBP-2 and human IGFBP-5. IGFBP mRNAs from follicles were identified by Northern blot hybridization using [32P]labeled complementary DNAs encoding ovine IGFBP-1 or -2, and rat IGFBP-4, -5, or -6. Uptake and organification of Na[125I] were measured by incorporation into trichloroacetic acid-precipitable material. Isolated thyroid follicles synthesized four species of IGFBPs in either 0H or 3H medium as detected by ligand blotting, of sizes 40-46, 34, 28, and 18 kilodaltons (kDa), respectively. The 32 kDa IGFBP was identified immunologically as IGFBP-2, whereas the 28 kDa and 18 kDa species were identified as IGFBP-5. Northern blot hybridization of total RNA from cells in 3H medium demonstrated an IGFBP-2 messenger RNA (mRNA) [1.4 kilobase (kb)], an IGFBP-4 mRNA (2.6 kb), and two IGFBP-5 mRNAs (6 kb and 1.8 kb). No IGFBP-1 or -6 mRNAs were detected. Incubation of cultured follicles with TSH (30-500 microU/ml) caused a dose-dependent decrease in the abundance of all IGFBP mRNAs and released proteins, which were reduced further by TSH together with cortisol (10 nM). When the inhibitory effect of TSH and cortisol was removed, IGFBP-2 mRNA increased within 3 h and was 7-fold greater within 12 h. IGFBP-2 did not appear in the conditioned medium until 12 h after TSH removal, along with the other IGFBP species.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Hormonal regulation and biological actions of insulin-like growth factor binding proteins in isolated ovine thyroid follicles. 750 36

We describe a case of recurrent hypoglycaemia associated with a hepatoma. During hypoglycaemia serum insulin was undetectable. Plasma insulin-like growth factor II (IGF-II) was not elevated although 71% of plasma IGF-II was present as big IGF-II (molecular weight 11 kDa) which probably represents a non-glycated form of pro-IGF-II. The GH response to hypoglycaemia was impaired and plasma levels of both IGF-I and the GH-dependent IGF binding protein (IGFBP-3) were low. A recently described unextracted assay directed against the first 21 amino acids of the E-domain (E-21) of proinsulin-like growth factor-II (pro-IGF-II) allows direct plasma estimation (plasma E-21) of larger molecular forms of IGF-II without interference from normal IGF-II and IGF binding proteins. Basal values were grossly elevated (23.7 and 23.8 nmol/l). Treatment with GH led to an increase in the mean plasma glucose across 24 hours (4.25 +/- 0.21 mol/l (mean +/- SEM) before treatment, compared with 4.86 mmol/l +/- 0.17 following GH (P < 0.01)) and a reduction in hypoglycaemic attacks. The treatment was associated with a rise in IGFBP-3 and small increases in insulin like growth factors. Subsequent treatment with the somatostatin analogue octreotide did not produce a significant change in plasma glucose levels or insulin-like growth factors. Two courses of intrahepatic adriamycin restored elevated levels of E-21 to normal. Total IGF-II remained normal and IGF-I increased. GH treatment was successfully withdrawn with no effect on plasma glucose or growth factor levels. The patient remained free from hypoglycaemia.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A case of hepatoma associated with hypoglycaemia and overproduction of IGF-II (E-21): beneficial effects of treatment with growth hormone and intrahepatic adriamycin. 752 21

This study was designed to determine whether the somatostatin analogue, octreotide, could prevent embryonic loss by normalizing increased uterine insulin-like growth factor-I (IGF-I) action related to hyperoestrogenaemia following superovulation. Superovulated immature and oestradiol-17beta-treated adult rats were infused with 100 or 300 microg/ml of octreotide respectively, or injected daily with 1 or 10 microg of octreotide from day 1 to day 3 of pregnancy. On day 3, embryos were collected from the oviducts and uteri. Uterine luminal fluid was subjected to embryo culture. The amounts of uterine IGF-I and IGF binding proteins (IGFBP) were determined by radioimmunoassay and ligand binding assay respectively. Octreotide infusion normalized uterine IGF-I action following superovulatory and oestradiol-17beta treatment, by reducing IGF-I concentrations and increasing IGFBP concentrations. Octreotide infusion increased the number of normal embryos by 2.7-fold and 1.7-fold in superovulated and oestradiol-17beta-treated rats respectively, and reversed the detrimental effects of uterine luminal fluid on embryonic development caused by superovulatory and oestradiol-17beta treatment. Daily injections with octreotide had similar but reduced effects in all parameters examined in both treatment groups. In conclusion, octreotide may reduce embryonic loss, at least in part, by normalizing IGF-I action following superovulation.
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PMID:A somatostatin analogue decreases embryonic loss following superovulation in rats by normalizing insulin-like growth factor-I action in the uterus. 915 22

The aim of the present study was to determine the effect of octreotide, a somatostatin analogue, on ovarian sensitivity for follicle stimulating hormone (FSH) in patients with polycystic ovary syndrome (PCOS). As the measure of ovarian sensitivity, the FSH threshold was determined in a case-control set-up. Eleven patients with PCOS were treated with FSH in a low dose step-up manner and subsequently received treatment with FSH combined with octreotide. The FSH threshold was found to be significantly higher during combined treatment. This increase was associated with a decrease in insulin-like growth factor-I (IGF-I) and IGF binding protein-3 (IGFBP-3) concentrations during treatment with octreotide, but not with a decrease in insulin concentrations. No differences were found between the two regimens, in number of follicles, in oestradiol concentrations on the day of human chorionic gonadotrophin (HCG) administration or in ovulation rate. With both treatments, there was a very low rate of multifollicular development. It can be concluded that octreotide lowers ovarian sensitivity for FSH through suppression of IGF-I/IGFBP-3 in patients with PCOS. However, this does not appear to affect follicular development during gonadotrophin stimulation, because the latter is controlled to a high degree by the use of a low dose step-up treatment schedule in these patients.
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PMID:Octreotide, a somatostatin analogue, alters ovarian sensitivity to gonadotrophin stimulation as measured by the follicle stimulating hormone threshold in polycystic ovary syndrome. 968 72

We here investigate the potential rescue of the relative hyposomatotropism of aging and obesity by 3-day pulsatile GHRH infusions (i.v. bolus 0.33 microg/kg every 90 min) in 19 healthy men of varying ages (18 to 66 years) and body compositions (12 to 37% total body fat). Baseline (control) and GHRH-driven pulsatile GH secretion (in randomly ordered sessions) were quantitated by deconvolution analysis of 24-h (10-min sampling) serum GH concentration profiles measured in an ultrasensitive (threshold 0.005 microg/l) chemiluminescence assay. GHRH infusion significantly increased the mean (24-h) serum GH concentration (0.3 +/- 0.1 basal vs 2.4 +/- 0.4 microg/l treatment; P = 0.0001), total daily pulsatile GH production rate (21 +/- 9.5 vs 97 +/- 17 microg/l/day; P = 0.01), GH secretory burst frequency (11 +/- 0.5 vs 17 +/- 0.3 events/day; P = <0.01), and mass of GH released per burst (1.1 +/- 0.4 vs 5.9 1 microg/l; P < 0.01), as well as serum IGF-I (261 +/- 33 vs 436 +/- 37 microg/l; P = 0.005), insulin (45 +/- 13 vs 79 +/- 17 mU/l; P = 0.0002), and IGF binding protein (IGFBP)-3 (3320 +/- 107 vs 4320 +/- 114 microg/l; P = 0.001) concentrations, while decreasing IGFBP-1 levels (16 +/- 1.2 vs 14 +/- 0.09 microg/l; P = 0.02). Serum total testosterone and estradiol concentrations did not change. GHRH treatment also reduced the half-duration of GH secretory bursts, and increased the GH half-life. GHRH-stimulated 24-h serum GH concentrations and the mass of GH secreted per burst were correlated negatively with age (R[value]:P[value] = -0.67:0.002 and -0.58:0.009 respectively), and percentage body fat (R:P = -0.80:0.0001 and -0.65:0.0005 respectively), but positively with serum testosterone concentrations (R:P = +0.55:0.016 and +0.53:0.019 respectively). GHRH-stimulated plasma IGF-I increments correlated negatively with age and body mass index, and positively with serum testosterone, but not with percentage body fat. Cosinor analysis disclosed persistent nyctohemeral rhythmicity of GH secretory burst mass (with significantly increased 24-h amplitude and mesor values) but unchanged acrophase during fixed pulsatile GHRH infusions, which suggests that both GHRH- and non-GHRH-dependent mechanisms can modulate the magnitude (but only non-GHRH mechanisms can modulate the timing) of somatotrope secretory activity differentially over a 24-h period. In summary, diminished GHRH action and/or non-GHRH-dependent mechanisms (e.g. somatostatin excess, putative endogenous growth hormone-releasing peptide deficiency etc.) probably underlie the hyposomatotropism of aging, (relative) obesity, and/or hypoandrogenemia. Preserved or increased tissue IGF-I responses to GHRH-stimulated GH secretion (albeit absolutely reduced, suggesting GHRH insensitivity in obesity) may distinguish the pathophysiology of adiposity-associated hyposomatotropism from that of healthy aging.
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PMID:Unequal impact of age, percentage body fat, and serum testosterone concentrations on the somatotrophic, IGF-I, and IGF-binding protein responses to a three-day intravenous growth hormone-releasing hormone pulsatile infusion in men. 970 80

The aim of this work was to study the effect of chronic activation of the immune system on the somatotropic axis. Accordingly, the changes in growth hormone (GH) secretion, circulating insulin-like growth factor-I (IGF-I) and IGF binding proteins (IGFBPs) in response to endotoxin lipopolysaccharide (LPS) administration were examined in adult male Wistar rats. Acute LPS injection (2.5, 25 or 250 microg/kg) increased serum corticosterone in a dose-dependent manner and decreased serum levels of insulin and IGF-I, serum GH concentration declined linearly as the LPS dose increased. Western ligand blot showed an increase in the 33 kDa band (corresponding to IGFBP-1 and IGFBP-2) in the rats that received the highest dose of LPS (250 microg/kg). Chronic LPS administration (250 microg/kg daily for 8 days) significantly decreased body weight, serum levels of IGF-I and pituitary GH content, whereas it increased circulating IGFBP-3 (47 kDa band), IGFBP-1 and IGFBP-2 (33 kDa band) and the 24 kDa band (which possibly corresponds to IGFBP-4). Serum concentration of corticosterone and hypothalamic somatostatin content were also increased by chronic LPS treatment. These data suggest that the decrease in GH and IGF-I secretion and the increase in circulating IGFBPs are important mechanisms in body weight loss during chronic inflammation.
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PMID:Effects of endotoxin lipopolysaccharide administration on the somatotropic axis. 979 64

The aim of this work was to study the effect of cyclosporine on the somatotropic axis. Accordingly, growth hormone (GH) secretion, circulating insulin-like growth factor I (IGF-I) and IGF binding proteins (IGFBPs) in response to cyclosporin A (CsA) treatment were examined in adult male Wistar rats. Cyclosporine administration (5, 10 or 20 mg/Kg daily) over 8 days did not modify the body weight, but it did decrease serum concentration of corticosterone and increased serum IGF-I and GH levels. Rats treated with 5 and 10 mg/Kg of cyclosporine had similar levels of serum IGFBPs to control rats, but there was an increase in circulating IGFBP-3 and IGFPB-1,2 in the group treated with 20 mg/Kg of CsA. The increase in circulating GH correlates with a decrease in pituitary GH content in CsA treated rats, with no modification in hypothalamic somatostatin content, suggesting an increase in pituitary GH release. In order to test this hypothesis, anterior pituitary cell cultures were exposed to different CsA concentrations during a 4 h incubation period. Cyclosporine increased GH secretion in cultured pituitary cells (p<0.05). These data suggest that cyclosporine increases circulating IGF-I and GH by stimulating pituitary GH release.
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PMID:The effect of cyclosporine administration on growth hormone release and serum concentrations of insulin-like growth factor-I in male rats. 1035 12

Hyperinsulinaemia and reduced insulin sensitivity are common features in patients with cirrhosis. Octreotide, a long-acting somatostatin analogue, is used in cirrhotic patients in the treatment of bleeding oesophageal varices. Octreotide has potent effects on the growth hormone (GH)/insulin-like growth factor I (IGF-I) axis in healthy subjects. but the effects on the GH/IGF-I axis in patients with cirrhosis have been described only briefly. The effects of a 12 h infusion of octreotide (bolus 0.75 microg/kg followed by 0.75 microg/kg/h) in 25 subjects (normals n=9, compensated cirrhotics n=8, decompensated cirrhotics n=8) were compared with those in placebo-treated controls (n=19) during fasting conditions. IGF-I, free IGF-I, IGF binding proteins (IGFBPs), insulin, C-peptide, GH and glucose were measured. Insulin resistance was calculated using the HOMA method. Octreotide reduced levels of total IGF-I in patients with compensated cirrhosis (p=0.03) and free IGF-I in decompensated cirrhosis (p<0.01). Insulin resistance was significantly reduced in normal subjects. whereas the reduction in insulin resistance did not reach statistical significance in patients with cirrhosis. In normal subjects, octreotide increased the IGFBP-1 area under curve threefold (p<0.01) and decreased IGFBP-3 levels (p<0.01), but these effects were blunted in the cirrhotic patients. Similarly, the reduction of insulin and C-peptide was blunted in the cirrhotic patients, whereas a significant reduction in GH was demonstrated in all groups. The effects of octreotide on the GH/IGF-I axis are mitigated in patients with cirrhosis and this may be a reflection of relative hyperinsulinaemia during octreotide treatment in these patients.
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PMID:Effects of octreotide on serum insulin-like growth factor I and insulin-like growth factor binding proteins in patients with cirrhosis. 1200 12

Mycobacterium avium is a common opportunistic infection of patients with acquired immunodeficiency syndrome (AIDS). We used the simian immunodeficiency virus (SIV)-infected rhesus macaque (Macaca mulatta) model to examine whether disseminated M. avium is associated with disruption of the somatotropic axis in AIDS. Macaques were followed prospectively, and body composition was determined by dual-energy x-ray absorption. Serum levels of insulin-like growth factor (IGF)-1, IGF binding protein-3, growth hormone (GH), and somatostatin were measured. SIV-infected macaques inoculated with mycobacteria had significant changes in body composition, perturbations of the somatotropic axis (characterized by increased GH/IGF-1 ratios) (day 0 [2.21] vs. day of death [DOD] [28.06]; P=.015, Mann-Whitney rank sum test), and increased serum somatostatin levels (day 0 [2.00 ng/mL] vs. DOD [8.58 ng/mL]; P=.026, Mann-Whitney rank sum test). These data document alterations in the somatotropic axis secondary to experimental disseminated M. avium infection and suggest that similar changes may contribute to alterations in body composition during AIDS.
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PMID:Wasting syndrome and disruption of the somatotropic axis in simian immunodeficiency virus-infected macaques with Mycobacterium avium complex infection. 1555 Dec 19

Somatostatin analogs (SAs) treat acromegaly by lowering pituitary GH secretion, which, in turn, lowers systemic IGF-I. The profound systemic effect is often greater than expected in the face of only partial GH suppression. Here we report that the SA SOM230 can also act by a nonpituitary-mediated inhibition of IGF-I action. SOM230 inhibited mammary development in intact and hypophysectomized female rats, a process requiring IGF-I. IGF-I overcame this inhibition. SOM230 also inhibited other actions of IGF-I (inhibition of apoptosis, phosphorylation of insulin receptor substrate-1, and cell division). SOM230 did not reduce IGF-I mRNA abundance in mammary gland but did stimulate IGF binding protein 5 (IGFBP5). IGFBP5 was 3.75 times higher in mammary epithelium of SOM230 than in placebo animals (P < 0.001). Administration of IGFBP-5 also inhibited GH-induced mammary development (P < 0.001). Measurement of sstr(1-5) (somatostatin subtype receptor) by real-time RT-PCR revealed that the mammary glands had an abundance of sstr(3) and lower amounts of sstr(4) and sstr(5) but no sstr(1) or sstr(2.) That mammary development was also inhibited to a lesser degree than SOM230 by octreotide, whose main action is through sstr(2), strongly suggests that sstr(3) is at least in part mediating the effects of the SAs. We conclude that 1) SAs inhibit IGF-I action in the mammary gland through a novel nonpituitary mechanism; 2) IGFBP-5, here shown to inhibit pubertal mammary development, might mediate the effect; and 3) Measurement of available sstr receptors in the mammary gland suggests that sstr(3) mediates the SA activity, but sstr(5) is also a possible mediator.
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PMID:SOM230 inhibits insulin-like growth factor-I action in mammary gland development by pituitary independent mechanism: mediated through somatostatin subtype receptor 3? 1622 73

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