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Effects of actinomycin D and cycloheximide on transcript levels of IGF‐I, actin, and albumin in hepatocyte primary cultures treated with growth hormone and insulin
Author(s) -
Johnson Thomas R.,
Trojan Jerzy,
Rudin Susan D.,
Blossey Betty K.,
Ilan Judith,
Ilan Joseph
Publication year - 1991
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.1080300204
Subject(s) - cycloheximide , biology , dactinomycin , rna , albumin , messenger rna , endocrinology , medicine , hepatocyte , protein biosynthesis , insulin , microbiology and biotechnology , actin , in vitro , biochemistry , gene
The stability of several RNA transcripts in cultured hepatocytes is known to increase when serum is omitted from the culture medium. In order to investigate possible mechanisms for this phenomenon, we examined the effects of actinomycin D and cycloheximide on the levels of actin, albumin, and insulin‐like growth factor I transcripts in primary cultures incubated in serumfree medium. The levels of IGF‐I and albumin transcripts per culture increased for the first 4 hours following addition of actinomycin D and then declined. The levels of actin transcripts and total RNA per culture declined immediately following actinomycin D addition in a manner consistent with exponential decay. IGF‐I and albumin transcript levels were relatively unaffected by cycloheximide, while actin transcript levels increased 7‐fold over 7 hours. The half‐lives of actin transcripts and total RNA were calculated to be 4.6 to 7.7 hours and 11 to 19 hours, respectively, with no statistically significant correlation with hormone treatment. The data suggest that the stability of albumin and IGF‐I transcripts, but not actin transcripts, is controlled in part by an actinomycin D‐sensitive process.