The effect of synthetic fragment 31–44 of human growth hormone on glucose uptake by isolated adipose tissue

Yudaev, N. A.; Pankov, Yu. A.; Keda, Yu. M.; Sazina, Elena; Осипова, Т. А.; Shwachkin, Yu.P.; Ryabtsev, M. N.

doi:10.1016/0006-291x(83)91041-0

Cited by 15 publications

(4 citation statements)

References 7 publications

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“…The growth-promoting activities of the modified GH preparations and the native human GH which served as precursor were assessed in the 9-day weight-gain test in hypophysectomized rats and compared to the International Standard of GH, Bovine (defined as 1.0 IU/mg). In this assay, the GH preparations were injected subcutaneously once daily for 9 days at the following daily doses (number of rats used per dose are given in parentheses): bovine GH standard, 20/~g (5) and 100/~g (5); unmodified human GH, 10 t~g (4) and 50 t~g (5); amidinated GH, 10 #g (4) and 50 /~g (5); citraconylated GH, 20/~g (8) and 100 ~g (7); trifluoroacetylated GH, 20/~g (5) and 100/~g (5); and camphorquinone-10-sulfonic acid-modified GH, 20 ~g (4) and 100 t~g (4). As shown in Table I, both amidinated GH and citraconylated GH retained substantial growth-promoting activity, having estimated potencies greater than 1 IU/mg.…”

Section: Resultsmentioning

confidence: 99%

“…Additionally, Lewis et al [2] reported that digestion of human GH with subtilisin resulted in a product which produced fasting hyperglycemia and glucose intolerance within 10 h after its administration to 0304-4165/85/$03.30 ~v 1985 Elsevier Science Publishers B.V. (Biomedical Division) dogs, whereas intact human GH was not diabetogenic in this assay. That proteolytic processing could also be important for the insulin-like property of GH has been suggested by recent findings that a synthetic peptide representing residues 31-44 of human GH exhibits significant in vitro insulin-like activity on glucose uptake by isolated rat epididymal adipose tissue [5].…”

Section: Introductionmentioning

confidence: 99%

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Trypsin-resistant forms of human growth hormone have diabetogenic and insulin-like activities

Cameron¹,

Kostyo²,

Kumar³

et al. 1985

Biochimica et Biophysica Acta (BBA) - General Subjects

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Although diabetogenic and insulin-like activities are intrinsic properties of the growth hormone (GH) molecule, it has been frequently suggested that the hormone must be proteolytically processed for these activities to be expressed. If this is correct, then derivatives of GH having resistance to appropriate proteolytic attack might not have diabetogenic and/or insulin-like activity. The purpose of the present study was to prepare derivatives of human GH that are resistant to digestion by trypsin and to determine whether they possess diabetogenic or insulin-like activity. Three derivatives were prepared from purified native human GH in which lysine residues were modified with methyl acetimidate, citraconic anhydride or S-ethyl-thioltrifluoroacetate, and one in which arginine residues were modified with camphorquinone-10-sulfonic acid. Comparisons of peptide maps of tryptic digests of these derivatives with that of unmodified human GH indicated that all four were resistant to proteolysis by trypsin. All of these trypsin-resistant forms of human GH were found to possess significant growth-promoting, diabetogenic and insulin-like activities, although all activities were attenuated to some extent in each derivative. The relative potencies of the human GH derivatives in a radioimmunoassay for human GH were somewhat similar to their order of potency in the growth-promoting and diabetogenic assays. These results suggest that if proteolytic processing of the GH molecule is involved in the expression of one or more of its biological activities, such processing probably does not involve a trypsin-like proteinase.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Trypsin-resistant forms of human growth hormone have diabetogenic and insulin-like activities

Cameron¹,

Kostyo²,

Kumar³

et al. 1985

Biochimica et Biophysica Acta (BBA) - General Subjects

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“…However, 20-kDa Met-hGH had only 20% the insulin-like activity of 22-kDa Met-hGH, and consequently we infer that the deleted region may be required for the full expression of activity, either because it contains a portion of the active site for this property or because the conformation of the 20-kDa variant interferes with the full expression of insulin-like activity. In this regard, a synthetic peptide corresponding to residues 31-44 of hGH has been reported to stimulate glucose uptake by isolated rat epididymal adipose tissue (23). On the other hand, it is worth noting that even structural modifications of the hGH molecule not involving amino acid deletions (e.g., S-carboxymethylation) frequently result in the attenuation of insulin-like activity (24).…”

mentioning

confidence: 99%

Biosynthetic 20-kilodalton methionyl-human growth hormone has diabetogenic and insulin-like activities.

Kostyo¹,

Cameron²,

Olson³

et al. 1985

Proc. Natl. Acad. Sci. U.S.A.

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The anterior pituitary gland produces a 20-kilodalton (kDa) variant of human growth hormone (hGH) that differs from the predominant 22-kDa form of hGH in that amino acid residues 32-46 are deleted. Previous work has suggested that the 20-kDa variant possesses the full growth-promoting and lactogenic activities of 22-kDa hGH but lacks its intrinsic diabetogenic and insulin-like activities. In the present study, recombinant DNA techniques were used to prepare biosynthetic 20-kDa hGH, and some of the biological properties of the purified hGH variant were examined. The biosynthetic 20-kDa hGH variant was found to share the propensity for aggregation exhibited by its native counterpart. Moreover, like the native variant, biosynthetic 20-kDa hGH possessed full growth-promoting activity in the weight gain test in hypophysectomized rats. However, contrary to previous work suggesting that native 20-kDa hGH lacks diabetogenic and insulin-like activities, biosynthetic 20-kDa hGH was found to have substantial diabetogenic activity when administered chronically to ob/ob mice and to possess approximately 20% the in vitro insulin-like activity of biosynthetic 22-kDa hGH on isolated epididymal adipose tissue of hypophysectomized rats. The diabetogenic and insulin-like activities of biosynthetic 20-kDa hGH cannot be ascribed to contamination of the hormone preparation with the 22-kDa form of hGH or with other diabetogenic or insulin-like pituitary peptides. Therefore, the results strongly suggest that diabetogenic and insulin-like activities are also intrinsic properties of the 20-kDa variant of hGH.A 20-kilodalton variant of human growth hormone (20-kDa hGH) has been isolated from human pituitary glands (1) and has been found to differ from the predominant 22-kilodalton form of hGH (22-kDa hGH) in that residues 32-46 are deleted (2, 3). The variant is produced in the human pituitary, because the nucleotide sequence encoding residues 32-46 is sometimes excised during the processing of hGH pre-mRNA to hGH mRNA (4). As a consequence, approximately 5-10%1 of the hGH present in the human pituitary is 20-kDa hGH (1). Physicochemical studies of 20-kDa hGH (3) suggest that its conformation is similar but not identical to that of 22-kDa hGH.The 20-kDa variant of hGH has been reported (1, 5) to have growth-promoting activity in the hypophysectomized rat equivalent to that of 22-kDa hGH. Moreover, its lactogenic activity in the pigeon crop sac assay equals that of 22-kDa hGH (1). On the other hand, Lewis et al. (5) reported that 20-kDa hGH lacked diabetogenic activity, in that it failed to produce hyperglycemia and glucose intolerance in dogs, when administered 10 hr prior to a glucose tolerance test. Also, this same group reported (6) that 20-kDa hGH lacked the acute insulin-like property of 22-kDa hGH, since the 20-kDa hGH variant failed to produce hypoglycemia and increase plasma free fatty acids when administered to hypophysectomized rats and did not increase glucose uptake or oxidation to CO2 by isolated rat adipose tissue wh...

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“…Comparison of amino acid sequences of a region (residues [27][28][29][30][31][32][33][34][35][36][37][38] of hGH with known tyrosine phosphorylation sites. The amino acid sequences of hGH (residues 27-38) (8), human gastrin (residues [21][22][23][24][25][26][27][28][29][30][31][32] (15, 16), polyoma middle T protein (residues 318-329) (9,10), and the oncoprotein of Rous sarcoma virus (RSV) (residues 408-419) (2) were aligned about their modified tyrosine residue.…”

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confidence: 99%

Phosphorylation of human growth hormone by the epidermal growth factor-stimulated tyrosine kinase.

Baldwin¹,

Grego²,

Hearn³

et al. 1983

Proc. Natl. Acad. Sci. U.S.A.

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In the present study, we have demonstrated that human growth hormone (hGH) can be phosphorylated by the epidermal growth factor (EGF)-stimulated tyrosine kinase of A431 cell membranes. Phosphotyrosine was the predominant phosphoamino acid released from phosphorylated hGH on partial acid hydrolysis. All five tyrosine-containing tryptic peptides of hGH are also phosphorylated by the EGF-stimulated tyrosine kinase. The highest phosphate incorporation was found for peptide T4 (residues 20-38), which is distinguished by a high frequency of acidic amino acids. The phosphorylated peptides have been characterized by HPLC and two-dimensional mapping on paper. Comparison with the labeled peptides obtained on tryptic digestion of phosphorylated hGH suggests that tyrosine phosphorylation is restricted to two tryptic peptides, T4 (tyrosine-28 or -35) and T6 (tyrosine-42). It is suggested that the absence of early insulin-like activity in the naturally occurring Mr 20,000 variant of hGH, which has an internal deletion spanning residues 32-46, may be a consequence of the loss of the tyrosine phosphorylation sites at residues 35 and 42.Comparison of amino acid sequences of a region (residues 27-38) of hGH with known tyrosine phosphorylation sites. The amino acid sequences of hGH (residues 27-38) (8), human gastrin (residues 21-32) (15, 16), polyoma middle T protein (residues 318-329) (9, 10), and the oncoprotein of Rous sarcoma virus (RSV) (residues 408-419) (2) were aligned about their modified tyrosine residue. A one-letter notation for abbreviating amino acid residues has been used (17); (, modified tyrosine residue.Considerable interest has recently been shown in the possible role of tyrosine phosphorylation in normal and malignant cellular growth. Although phosphorylation accounts for <0.1% of the phosphoamino acid pool in normal cells (1), levels of phosphotyrosine increase 10-fold after retroviral infection as a result of the tyrosine-kinase activity that is an intrinsic property of the transforming proteins of several RNA tumor viruses (2, 3). Stimulation of cellular growth by polypeptides such as epidermal growth factor (EGF) (4, 5), platelet-derived growth factor (6), and insulin (7) may also be related to the tyrosine kinase activities associated with the membrane receptors for these three polypeptides.Human growth hormone (hGH), somatotropin, is a singlechain polypeptide hormone of Mr 22,000 (8). The amino acid sequence of hGH between residues 30 and 40 is reminiscent of the tyrosine phosphorylation site in the middle T protein of polyoma virus (9, 10), other viral oncoproteins (2, 11-13), and gastrin (14) in that it contains a tyrosine residue preceded by several adjacent glutamic residues (Fig. 1). Therefore, we have tested hGH as a substrate for the tyrosine kinase associated with the EGF receptor (4, 5). A useful control occurs naturally in the Mr 20,000 structural variant of hGH (18), which is a significant component (10%) of all hGH preparations from pituitary extracts. The amino acid sequence of th...

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The effect of synthetic fragment 31–44 of human growth hormone on glucose uptake by isolated adipose tissue

Cited by 15 publications

References 7 publications

Trypsin-resistant forms of human growth hormone have diabetogenic and insulin-like activities

Trypsin-resistant forms of human growth hormone have diabetogenic and insulin-like activities

Biosynthetic 20-kilodalton methionyl-human growth hormone has diabetogenic and insulin-like activities.

Phosphorylation of human growth hormone by the epidermal growth factor-stimulated tyrosine kinase.

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