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S Kronheim

Publications and source records attributed to S Kronheim.

35 records · Page 2Linked to original sources
PubMed1978

Tissue growth hormone release inhibiting hormone-like immunoreactivity in experimental hypothyroidism and hypopituitarism.

Hypothyroidism in rats was associated with an increase in immuno-reactive GH-RIH in brain, pancreas and gut, although release from the latter may be diminished as portal GH-RIH-like immunoreactivity was lower than control values. Hypophysectomy resulted in a depletion of immunoreactive GH-RIH in the septum and preoptic area of the brain and gastric antrum, but an increase in pancreas; portal venous GH-RIH-like immunoreactivity was not different from control concentrations, possibly reflecting both elevated and lowered immunol-reactive GH-RIH in different regions of tissue subserved by the portal vein. Inferior vena caval GH-RIH-like immunoreactivity was always lower than in the portal vein and was not influenced by tissue pertubations in hypothyroidism and hypopituitarism which made regional blood sampling of great important in evaluating tissue changes.

Animals↗
PubMed1978

Somatostatin-like immunoreactivity in rat blood. Characterization, regional differences, and responses to oral and intravenous glucose.

Somatostatin-like immunoreactivity (SLI) has been demonstrated by radioimmunoassay (RIA) in rat serum using an antiserum specific for somatostatin and cross-reacting maximally with the biologically important area on the peptide. The RIA has a sensitivity of 35 pg/ml. SLI dilutes in parallel with synthetic somatostatin standard in the RIA and shows characteristics similar to synthetic somatostatin on Sephadex G-25 (f) gel chromatography eluting largely as a single peak with 1 M acetic acid. Significant regional differences in serum SLI are present. A positive gradient was found in paired samples from aorta (mean+/-SEM, 0.304+/-0.024 ng/ml) and portal vein (0.495+/-0.047 ng/ml) consistent with the known presence of somatostatin in gut and pancreas, and a negative gradient was noted between paired samples from portal vein (0.523+/-0.076 ng/ml) and hepatic vein (0.290+/-0.048 ng/ml) indicating hepatic clearance. No significant differences were demonstrated between aorta and confluence of cerebral venous sinuses or between aorta and inferior vena cava (IVC). After intragastric glucose, a significant and marked elevation of portal SLI was observed, maximal at 5 min (0.416+/-0.137 vs. 1.55+/-0.30 ng/ml at 5 min). A significant biphasic elevation of portal SLI also occurred after intravenous glucose. After both routes of glucose administration, the patterns of portal SLI followed closely those of portal glucose and insulin. By contrast, IVC SLI failed to reflect these changes.Thus, SLI in the rat shows chromatographic similarity with synthetic somatostatin. Regional differences in serum levels are marked; the highest concentrations being found in the portal venous effluent of pancreas and gut. Furthermore, glucose causes elevation of portal SLI in a pattern similar to portal insulin and glucose and without concomitant elevation in IVC. This differential elevation of SLI after glucose is consistent with a hormonal action within the portal system as a direct effect of somatostatin on the liver has previously been demonstrated. In addition, the liver is important in the clearance of portal SLI, possibly to prevent extraportal effects in response to gut and pancreatic stimulation. Finally, it is clear that regional sampling of serum for SLI measurement may be critical in the investigation of the putative physiological roles for somatostatin.

Animals↗
PubMed1978

The characterization of somatostatin-like immunoreactivity in human serum.

We describe the characterization of somatostatin-like immunoreactivity (SRIF-LI) found by radioimmunoassay (RIA) to be present in normal human serum. Degradation by serum of 125I-Tyr1 SRIF in the assay, as assessed by chromatoelectrophoresis and immunoprecipitation, was overcome by using EDTA in the assay buffer and Trasylol in the blood samples. Serum samples thus obtained from 48 normal subjects revealed a bimodal distribution of SRIF-LI; 92 per cent (group 1) had a mean level of 0.274 +/- 0.009 ng. per milliliter. What was measured in these sera showed identity to synthetic SRIF on serial dilutions, Sephadex G-25 chromatography, and thin-layer chromatography, and it was shown to be immunoreactive by an antibody-Sepharose affinity system. Higher levels (1.0 +/- 0.041 ng. per milliliter) were found in 8 per cent of the sera; 50 per cent of this material behaved identically as serum SRIF-LI from group 1. The remainder proved to be heterogeneous, consisting of two peaks of large molecular weight, both of which shared immunologic identity with synthetic SRIF as shown by binding to the antibody-Sepharose affinity system. Their further nature is unknown.

Adult↗
PubMed1977

The characterization of growth hormone release inhibiting hormone-like immunoreactivity in normal urine.

Using a previously described radioimmunoassay for growth hormone release inhibiting hormone (GH-RIH), the presence of GH-RIH-like immunoreactivity in urine has been characterized by demonstrating mobility identical to synthetic GH-RIH standard on two sephadex gel chromatographic systems, and parallelism of dilutions of the sephadex fractions with synthetic GH-RIH. Furthermore, 74% of the sephadex fraction cross-reacting in the immunoassay bound to antibody conjugated to sepharose and could be eluted by 1 M acetic acid. This immunospecific eluate showed identity with synthetic GH-RIH on both ion exchange and thin layer chromatography. Thus GH-RIH-like immunoreactivity is present in normal urine; this may have potential relevance in the search for a physiological role for this peptide.

Humans↗
PubMed1977

An investigation into gonadal dysfunction in patients with idiopathic haemochromatosis.

Endocrine studies were performed on twelve patients with proven idiopathic haemochromatosis. Basal gonadotrophin levels and/or their responses to LH releasing hormone (LHRH) were low in nine patients, all of whom showed low plasma testosterone levels and clinical evidence of hypogonadism. Those patients with normal gonadotrophin responses had higher testosterone values, suggesting that the poor testosterone secretion was primarily due to inadequate trophic stimulation. No patient showed hypothyroidism of hypothalamic-pituitary origin, while the cortisol response to hypoglycaemia was normal in all six patients studied. GH responses were more variable and difficult to interpret, since the number of the patients studied was small and the degree of hypoglycaemia after insulin was unpredictable.

Adult↗
PubMed1976

Somatostatin, 1976.

Somatostatin, a growth hormone release-inhibiting factor, isolated originally from the hypothalamus, has been shown to have widespread effects on brain and endocrine and exocrine pancreatic and gut function. Furthermore, it has a widespread distribution in the CNS, gut and C cells of the thyroid -- cells which probably migrated originally from the neural crest during development. While the pharmacological effects of somatostatin are diffuse, its physiological role is at present unknown, but in view of its concentration in synaptosomal fractions of neural tissue, it may have a neurotransmitter or a synaptic modulator function.

Animals↗
PubMed1976

A radioimmunoassay for growth hormone release-inhibiting hormone: method and quantitative tissue distribution.

A specific antiserum has been produced to haemocyanin conjugaed synthetic growth hormone release inhibiting hormone (GHRIH). This has allowed the development of a radioimmunoassay for GHRIH sensitive to 5 pg/tube. GHRIH content in 2 m acetic acid extracts of rat tissues have been measured and show the majority to be CNS-especially hypothalamus and septum and preoptic areas with substantial amounts in spinal cord and thalamus. Extra neurological localization in pancreas, gastric antrum, colon and thyroid have been demonstrated.

Animals↗
PubMed1975

The effect of alanine infusions on growth hormone, insulin, and glucose in protein-calorie malnutrition.

In view of the previously reported inverse correlation between the elevated serum growth hormone (HGH) and low alanine in children with protein-calorie malnutrition (PCM), 30-min alanine infusions were performed in five children with PCM and 12-hr infusions in four children before and after therapy. These infusions did not lower basal HGH or improve its glucose suppressibility in untreated PCM, excluding a feedback relationship between HGH and alanine. There was no insulinotropic effect during 30-min infusions, but an improved insulin response to glucose after the 12-hr alanine infusion was found in three of four children before therapy. Plasma glucose rose slightly during alanine infusion in three of five children before treatment, but the magnitude of change was small and the relevance unclear.

Alanine↗
PubMed1975

Disappearance rates of plasma growth hormone after intravenous somatostatin in renal and liver disease.

Plasma immunoreactive growth hormone (hGH) was measured before, during and after the administration of intravenous somatostatin to 3 patients with chronic renal failure and 4 with severe liver disease who had elevation of basal hGH. During somatostatin infusion, the hGH levels declined acutely in a linear fashion when log hGH was plotted against time. Rather surprisingly, the plasma hGH half disappearance time (t 1/2) was 27 min and 18 min in liver and renal disease respectively. These values do not differ from data obtained on normal subjects using exogenous hGH, labelled or unlabelled. Control data on normal subjects using this technique are not available as it was not possible to measure subnormal levels of plasma hGH with the required precision. It is possible that our findings of plasma hGH T 1/2 in liver and renal disease within the normal range reported using exogenous hGH might suggest that high levels of plasma hGH found in these two diseases are primarily caused by hypersecretion rather than impaired clearance.

Growth Hormone↗