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Biomedical subjects

H Sievertsson

Publications and source records attributed to H Sievertsson.

At least 19 recordsLinked to original sources
PubMed1979

Tripeptide analogues of melanocyte-stimulating hormone release-inhibiting hormone (Pro-Leu-Gly-NH2) as inhibitors of oxotremorine-induced tremor.

Fourteen di- and tripeptide analogues of MIF, Pro-Leu-Gly-NH2, have been synthesized and assayed for inhibition of oxotremorine-induced tremor. Replacement of Pro by HCO-Pro or cyclopentanecarboxylic acid gave inactive analogues, while some peptides of the general structure less than Glu-Leu-Gly-NR1R2 were highly active. Thus, R1 = C3H8 and R2 = H gave 4 times the activity of MIF, R1 = I-C3H8 and R2 = H gave 13 times the activity of MIF, and R1 = R2 = CH3 gave 29 times the activity of MIF. cyclo(-Pro-Leu-), Pro-Lys-Gly-NH2, and Pro-Arg-Gly-NH2 had no activity. Apparently, small modifications in the structure of MIF can yield highly active analogues with potential clinical value, e.g., in the treatment of Parkinson's disease or mental depression.

Animals↗
PubMed1977

On the optimal dosage of Pro-Leu-Gly-NH2 (MIF) in neuropharmacological tests and clinical use.

Pro-Leu-Gly-NH2 (MIF) inhibits the tremor induced by oxotremorine. Objective measurement of this tremor permits the drawing of a dose-effect curve. The inhibitory effect of the peptide increases linearly with increasing doses until an optimum is reached (between 30 and 40 mg/kg i.p.). At still higher doses the peptide is inactive. The same phenomenon is observed with analogues of MIF. This finding may have important bearings on the interpretation of clinical and experimental data obtained with MIF.

Animals↗
PubMed1977

Studies on the mechanism of somatostatin action on insulin release. V. Effect of somatostatin analogues on arginine induced release of insulin and glucagon from the perfused rat pancreas.

Eighteen analogues of somatostatin have been used in order to elucidate the structure-activity relationship of the peptide on the release of insulin and glucagon from the isolated perfused rat pancreas. Neither the amino terminal nor a free carboxyl terminal seemed to be essential for the activity of the cyclic peptide. Addition of amino acids to the amino terminal did not decrease the activity. On the other hand, minor changes in the structure of linear somatostatin, which lead to the loss of ability to form a cyclic peptide, impaired the activity. Deletion of Asn5 was accompanied by decreased action on glucagon but not on insulin release. It seems that the major actions of somatostatin on the pancreas are bound to the amino acid sequence 4-13 in the molecule and to the ability of the molecule to cyclize.

Amino Acid Sequence↗
PubMed1976

Binding of somatomedins and insulin to plasma membranes prepared from rat and monkey tissue.

Particulate membranes prepared from a variety of monkey and rat tissues were shown to have specific binding sites for somatomedin A. Binding to talc on the other hand showed no specificity, and the sensitivity was less. The membrane-bound somatomedin A was displaced by somatomedin A in concentrations between 0.01 and 5 U/ml. Of the other hormones tested only insulin in high concentrations could interfere with the binding of labelled somatomedin A to tissue membranes. Membranes prepared from a number of rat and monkey tissues also contained binding sites for insulin. Somatomedin A could interfere with the binding of labelled insulin. No binding was observed for somatomedin B in the tissues studied.

Animals↗
PubMed1976

Somatomedin A in human serum, determined by radioreceptor assay.

Somatomedin A was determined by radioreceptor assay in serum from patients with various disorders. The mean values of somatomedin A in serum from 20 adult subjects, 21 patients with acromegaly, and 17 patients with hypopituitary dwarfism were 1.08 +/- 0.08, 3.02 +/- 0.33 and 0.44 +/- 0.03 U/ml, respectively. In children below 2 years of age, low levels were found (mean 0.40 +/- 0.04 U/ml). Normal levels were found in patients with Turner's syndrome and primary hypothyroidism, increased levels in uraemic patients, and decreased levels in Laron dwarfs.

Acromegaly↗
PubMed1975

Somatomedins.

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Adipose Tissue↗