TY - JOUR
T1 - Differences in the cellular processing of Asp(B10) human insulin compared with human insulin and Lys(B28)Pro(B29) human insulin
AU - Hamel, Frederick G.
AU - Siford, Gerri L.
AU - Fawcett, Janet
AU - Chance, Ronald E.
AU - Frank, Bruce H.
AU - Duckworth, William C.
N1 - Funding Information:
From the Research Service, Department of Veterans Affairs Medical Center, Omaha; Department of Internal Medzcine, Umversity of Nebraska Medical Center, Omaha, NE; and Lilly Research Laboratories, Indianapolis, IN. Submitted July 7, 1998; accepted November 2, 1998 Supported by the Medical Research Service of the Department of Veterans Affairs, Omaha, HE, and a grant from Eli Lilly and Company, Indianapohs, IN. Address reprint requests to Frederick G. Hamel, PhD, Department of Veterans Affairs Medical Center, 410l Woolworth Ave, Omaha, NE 68105. Copyright © 1999 by W.B. Saunders Company 0026-0495/99/4805-0013510.00/0
PY - 1999
Y1 - 1999
N2 - Cellular metabolism studies were performed comparing human insulin with two rapid-acting analogs, Lys(B28)Pro(B29) insulin (LysPro] and Asp(B10) insulin (B10-Asp). B10-Asp bound to isolated hepatocytes at 37°C to a greater extent than LysPro or native insulin, which were equivalent. The rate of degradation was similar for the three materials, resulting in a significant reduction in the degraded/bound ratio for the B10 analog. The processing of membrane-bound material was examined by incubating cells with hormone at 4°C, removing unbound insulin, and incubating the cells at 37°C. Again, binding was greater for B10-Asp versus LysPro or native insulin, with a reduction in the degraded/bound ratio. Hormone internalization and processing was examined by an acid wash of cells incubated with 125I(A14)- labeled hormone to remove surface-bound materials. The processing rate was slower for B10-Asp versus LysPro or native insulin. Cell extraction and examination on molecular-sieve chromatography confirmed that B10-Asp was processed at a slower rate than either LysPro or native insulin. Intact B10- Asp was found in the cell after 4 hours, whereas all native insulin and LysPro were degraded by 90 to 120 minutes. B10-Asp also caused a greater incorporation of thymidine into DNA in cultured cells than LysPro or native insulin, which were similar. These data show that the cellular processing of LysPro is essentially identical to that of native insulin. However, B10-Asp has markedly different properties and is processed much more slowly. The prolonged cell residence time of B10-Asp could contribute to its greater effects on cell growth and mitogenesis.
AB - Cellular metabolism studies were performed comparing human insulin with two rapid-acting analogs, Lys(B28)Pro(B29) insulin (LysPro] and Asp(B10) insulin (B10-Asp). B10-Asp bound to isolated hepatocytes at 37°C to a greater extent than LysPro or native insulin, which were equivalent. The rate of degradation was similar for the three materials, resulting in a significant reduction in the degraded/bound ratio for the B10 analog. The processing of membrane-bound material was examined by incubating cells with hormone at 4°C, removing unbound insulin, and incubating the cells at 37°C. Again, binding was greater for B10-Asp versus LysPro or native insulin, with a reduction in the degraded/bound ratio. Hormone internalization and processing was examined by an acid wash of cells incubated with 125I(A14)- labeled hormone to remove surface-bound materials. The processing rate was slower for B10-Asp versus LysPro or native insulin. Cell extraction and examination on molecular-sieve chromatography confirmed that B10-Asp was processed at a slower rate than either LysPro or native insulin. Intact B10- Asp was found in the cell after 4 hours, whereas all native insulin and LysPro were degraded by 90 to 120 minutes. B10-Asp also caused a greater incorporation of thymidine into DNA in cultured cells than LysPro or native insulin, which were similar. These data show that the cellular processing of LysPro is essentially identical to that of native insulin. However, B10-Asp has markedly different properties and is processed much more slowly. The prolonged cell residence time of B10-Asp could contribute to its greater effects on cell growth and mitogenesis.
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U2 - 10.1016/S0026-0495(99)90059-8
DO - 10.1016/S0026-0495(99)90059-8
M3 - Article
C2 - 10337862
AN - SCOPUS:0032895627
VL - 48
SP - 611
EP - 617
JO - Metabolism: Clinical and Experimental
JF - Metabolism: Clinical and Experimental
SN - 0026-0495
IS - 5
ER -