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Biomedical subjects

E R Froesch

Publications and source records attributed to E R Froesch.

At least 199 records · Page 11Linked to original sources
PubMed1977

Decrease of non-suppressible insulin-like activity after pancreatectomy and normalization by insulin therapy.

Non-suppressible insulin-like activity (NSILA-S) was determined in 5 dogs before and after pancreatectomy and again during insulin therapy. All NSILA-S determinations were carried out on serum samples which were passed over Sephadex G-50 columns equilibrated with 1 M acetic acid. The levels of NSILA-S decreased drastically shortly after pancreatectomy and rose slowly after institution of insulin therapy, to normal levels. During the period of severe diabetes after pancreatectomy the concentration of growth hormone was elevated. These findings indicate that 1) the pancreas cannot be the site of synthesis and release of NSILA-S, 2) NSILA-S levels do not always parallel growth hormone levels and 3) the synthesis and secretion of NSILA-S among other factors is under the control of insulin.

Animals↗
PubMed1977

The influence of hypophysectomy on NSILA concentrations in the dog: evidence for partially pituitary-independent regulation.

Non-suppressible insulin-like activity (NSILA) was determined in 5 dogs before and after hypophysectomy. All NSILA determinations were carried out on serum samples after acidic Sephadex G-50 chromatography by two different assay systems, i.e. a bioassay and a protein binding assay. The levels of NSILA decreased significantly after hypophysectomy and returned to near normal levels after 2 weeks. T3-, T4- and cortisol levels were drastically reduced during the entire period of the experiment. Several GH determinations after hypophysectomy revealed very low levels. Insulin-induced hypoglycaemia failed to provoke a rise of GH levels as late as 4 months after hypophysectomy. These findings indicate that: 1) The pituitary gland cannot be the site of synthesis of NSILA. 2) NSILA concentrations in the dog are maintained at a near normal level in the presence of very low growth hormone and thyroid hormone concentrations, so that these latter hormones do not appear to be the only regulatory factors concerned in NSILA synthesis.

Animals↗
PubMed1977

Determination of nonsuppressible insulin-like activity in human serum by a sensitive protein-binding assay.

We describe a sensitive protein-binding assay for non-suppressible insulin-like activity in human serum. It can detect as little as 0.2 microunits (corresponding to 0.5 ng) of the activity in 0.4 ml of the assay mixture. It is measured in a low-molecular-weight fraction (termed "biological material") obtained by chromatography of serum on Sephadex G-50 in 1 mol/liter acetic acid. This fraction has been shown earlier to contain nearly all this billogically active material that is present in serum. A partially purified carrier protein from human serum is used as the binding protein; different concentrations of a partially purified preparation of material with the activity serve as standards, which compete with 125l-labeled tracer for binding. Biological material dilutes more or less in parallel with the standard over a 10-fold concentration range. In the chromatographed serum fractions, displacing activity appears between 50 and 80% bed volume, with the peak at 60%, and coincides with the distribution and the peak of radioactivity obtained by chromatography of tracer. A good correlation (r = 0.88) is observed between the values determined for this activity in the rat fat-pad assay and the protein-binding assay, although the latter yields about two fold higher results (190 +/- 37 milliunits/liter vs. 345+- 65 milliunits/liter, mean values for 18 normal sera). Values determined in the protein-binding assay are decreased in hypopituitary patients (183 +/- 27 milliunits/liter) and increased in acromegalics (486 +/- 88 milliunits/liter), in accord with the results of the bioassay (68 +/- 21 milliunits/liter for hypopituitary patients, 293 +/- 53 for acromegalics).

Adolescent↗
PubMed1976

[Malignant hyperthermia: attempt at an early diagnosis by means of determination of creatine phosphokinase (CPK) and its isoenzymes].

Creatinphosphokinase (CPK) was elevated in sera of patients with malignant hyperthermia and in sera of some of their relatives. Only the MM-isoenzyme (but not the MB- or the BB-isoenzyme) could be detected by paperchromatographic analysis. In some of the patients elevation of muscle aldolase was also observed. Thus, the appearance of the BB-isoenzyme in sera of patients with malignant hyperthermia, as described by another group of investigators, was not confirmed. No specific screening method exists as yet to detect patients with a high risk of developing this often lethal reaction to anesthesia. However, in patients without muscle disease or trauma and without prior i.m. injections, myocardial infarction or major physical strain, elevation of CPK in serum should be interpreted as meaning that malignant hyperthermia may develop during anesthesia. The pathophysiology of malignant hyperthermia is discussed.

Creatine Kinase↗
PubMed1976

Disorders of fructose metabolism.

There are fundamental differences between the metabolic fate of fructose and of glucose. Whereas the metabolism of glucose is controlled by hormones such as insulin, fructose uptake and phosphorylation in the liver occurs independently of hormones and its ultimate metabolic fate is unpredictable. Essential fructosuria, a harmless inherited anomaly of fructose metabolism, is the least harmful of the disorders of fructose metabolism. Hereditary fructose intolerance and fructose-1,6-diphosphatase deficiency are discussed in greater detail with regard to biochemical abnormalities and clinical aspects. HFI is most serious in bottle-fed infants who cannot reject their sucrose-containing diet. Patients with HFI will have no clinical symptoms if kept on a fructose-free diet. In contrast, patients with fructose-1,6-diphosphatase deficiency can tolerate frucose. However, severe infections precipitate attacks of hypoglycaemia and lactic acidosis.

Aging↗
PubMed1976

Nonsuppressible insulin-like activity and thyroid hormones: major pituitary-dependent sulfation factors for chick embryo cartilage.

Serum from hypothyroid hypophysectomized rats did not stimulate sulfation or incorporation of amino acids into chick embryo sterna. When such rats were treated for a short time with growth hormone (somatotropin), their serum stimulated incorporation both of sulfate and of amino acids. The different actions of the two types of sera were not due to changes in thyroid state. The results support the existence in serum of a sulfation factor for chick embryo cartilage that is dependent upon growth hormone. Highly purified preparations of nonsuppressible insulin-like activity from human serum stimulated incorporation of amino acids, and of uridine into RNA, in chick embryo sterna in vitro; chondrocytes prepared from this tissue had specific high-affinity binding sites for this insulin-like activity. However, sulfate incorporation was stimulated very little, unless serum from hypothyroid hypophysectomized rats was also present. When L-3,5,3'-triiodothyronine was added as well, the stimulation was enhanced further. From these and other experiments, we conclude that (i) nonsuppressible insulin-like activity or a closely related peptide is the growth-hormone-dependent growth and sulfation factor for chick embryo cartilage: (ii) a second, unidentified factor must be present for the insulin-like activity to stimulate sulfation; and (iii) stimulation of sulfation by thyroid hormones in vitro is additive to that of nonsuppressible insulin-like activity.

Animals↗
PubMed1976

Non-suppressible insulin-like activity and sulphaton activity in serum extracts of normal subjects, acromegalics and pituitary dwarfs.

Non-suppressible insulin-like activity (NSILA) is a term used for a variety of substances in serum, excluding insulin, which promote glucose uptake of adipose tissue and diaphragm in vitro. NSILA-S is a peptide with a molecular weight of 7000 which is soluble in acid ethanol and which has been purified on a large scale from human serum. This study describes a simple chromatographic one step procedure by which NSILA-S can be extracted and quantitatively measured in individual sera. Using Sephadex G-75 equilibrated with 1 M acetic acid, NSILA-S was detected only in one peak containing small molecular peptides. NSILA-S obtained with this one step chromatographic procedure exerted all the effects of purified NSILA-S including sulphation activity on the rat cartilage. All chromatographic fractions with NSILA-S also had sulphation activity. Both, NSILA-S and sulphation activity were increased in acromegalics and decreased in pituitary dwarfs. It is suggested that one molecule in serum is responsible for both activities which are, at least in part, under the control of growth hormone.

Acromegaly↗
PubMed1975

The NSILA-s receptor in liver plasma membranes. Characterization and comparison with the insulin receptor.

NSILA-s (nonsuppressible insulin-like activity, soluble in acid ethanol) is a serum peptide that has insulin-like and growth-promoting activities. We have demonstrated previously that liver plasma membranes possess separate receptors for NSILA-s and insulin and have characterized the insulin receptor in detail. In the present study we have characterized the properties and specificity of the NSILA-s receptor and compared them to those of the insulin receptor in the same tissue. Both 125I-NSILA-s and 125I-insulin bind rapidly and reversibly to their receptors in liver membranes; maximal NSILA-s binding occurs at 20 degrees while maximal insulin binding is seen at 1-4 degrees. The pH optimum for NSILA-s binding is broad (6.0 to 8.0), in contrast to the very sharp pH optimum (7.5 to 8.0) for insulin binding. Both receptors exhibit a high degree of specificity. With the insulin receptor, NSILA-s and insulin analogues compete for binding in proportion to their insulin-like potency: insulin greater than proinsulin greater than NSILA-s. With the NSILA-s receptor, NSILA-s is most potent and the order is reversed: NSILA-s greater than proinsulin greater than insulin. Furthermore, six preparations of NSILA-s which varied 70-fold in biological activity competed for 125I-NSILA-s binding in order of their potencies. NSILA-s which had been inactivated biologically by reduction and aminoethylation and growth hormone were less than 1/100,000 as potent as the most purified NSILA-s preparation. Purified preparations of fibroblast growth factor, epidermal growth factor, nerve growth factor, and somatomedins B and C were less than 1% as effective as NSILA-s in competing for the 125I-NSILA-s suggesting that these factors act through other receptors. In contrast, somatomedin A was 10% as active as NSILA-s and multiplication-stimulating activity was fully as active as NSILA-s in competing for the NSILA-s receptor. Analysis of the data suggests that there are approximately 50 times more insulin receptors than NSILA-s receptors per liver cell, while the apparent affinity of NSILA-s receptors is somewhat higher than that of the insulin receptor.

Animals↗
PubMed1975

[The therapy of diabetic coma: quantitative value of insulin loss on the infusion instruments].

The loss of insulin due to adsorption to glass and tubing has been quantitatively determined. The properties of albumin, plasma protein, gelatin, heparin and Rheomacrodex in the prevention of insulin adsorption have been tested. The loss of insulin given by intravenous infusion is reproducible and constant for any given situation. The loss of insulin increases as the ratio of volume to glass surface decreases and as the time of contact between insulin and glass is prolonged. There is an almost linear relationship between insulin loss and insulin concentration, as would be expected if insulin binding by glass was an unspecific phenomenon. Albumin and plasma protein almost completely prevent insulin adsorption. In most clinical situations the loss of insulin through adsorption to glass and tubing can be ignored, and hence no albumin or plasma protein needs to be added to the solution.

Adsorption↗
PubMed1975

Increased sensitivity of diabetic rat adipose tissue towards the lipolytic action of epinephrine.

Adipose tissue from streptozotocin-diabetic rats exhibits half-maximal lipolytic responses (FFA, glycerol release, increase in tissue FFA) to epinephrine at hormone concentrations 5-10 times lowere than those required for half-maximal stimulation of lipolysis in adipose tissue from normal rats. The lipolytic response to epinephrine also occurs more promptly and the antilipolytic effect of insulin in the presence of submaximal epinephrine conceptrations is much less pronounced than in normal tissue. In contrast, diabetic adipose tissue is less responsive to ACTH and glucagon than normal tissue. Half-maximal lipolytic responses are elicited by similar dibutyryl cyclic AMP concentrations in both tissues. Insulin treatment of diabetic rats during 24 hrs restores the lipolytic response of their adipose tissue to epinephrine to nearly normal. Our findings point to an abnormality of diabetic adipose tissue possibly related to the hypersensitivity of catecholamines encountered in denervated organs which are adrenergically innvervated. They are consistent with present concept of different hormone discriminators on the fat cell membrane and offer a further explanation for increased FFA mobilization in the diabetic state.

Adipose Tissue↗