In vitro secretion of insulin-like growth factor-binding proteins from liver of striped bass, Morone saxatilis.
In vitro secretion of insulin-like growth factor-binding proteins (IGFBPs) from liver of striped bass (sb: Morone saxatilis) was studied using a simple organ-culture system. Liver cubes (1 mm3) were cultured in minimum essential medium with Earle's salts containing 0.1% bovine serum albumin and 100 U/ml penicillin in 5% CO2/95% O2 at 16 degrees. The amount of double-stranded DNA in these cultured liver cubes did not change by 192 hr in the culture, but decreased by 216 hr. Four IGFBPs (a 23- to 24-kDa protein, a 28- to 30-kDa protein, a 35- to 39-kDa protein, and an 85- to 90-kDa protein) were identified in striped bass serum by Western ligand blotting; two of these IGFBPs, 23-24 kDa (sbIGFBP-1) and 28-30 kDa (sbIGFBP-2), were consistently detected in culture media by Western ligand blot analysis. The intensity of the blot for sbIGFBP-2 was consistently greater than that of sbIGFBP-1, which was no longer secreted after 96 hr in culture. The effects of hormones and growth factors on IGFBP secretion by liver tissue were measured after 48 hr in culture. sbIGFBP-1 in the medium was significantly decreased by adding ovine prolactin (10 micrograms/ml), bovine insulin (100 micrograms/ml), and bovine IGF-I (100 ng/ml), but was increased by 17 beta-estradiol (E2: 5 and 50 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)
Fukazawa
Y
Y
Department of Integrative Biology, University of California, Berkeley 94720, USA.
Siharath
K
K
Iguchi
T
T
Bern
H A
HA
D000818:Animals; D001492:Bass / Q000378:metabolism*; D015153:Blotting, Western; D002417:Cattle; D046508:Culture Techniques; D004247:DNA / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology; D005934:Glucagon / Q000494:pharmacology; D013006:Growth Hormone / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D018969:Insulin-Like Growth Factor Binding Proteins / Q000235:genetics / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D008099:Liver / Q000737:chemistry / Q000378:metabolism*; D011388:Prolactin / Q000494:pharmacology; D012756:Sheep; D013739:Testosterone / Q000494:pharmacology; D013974:Thyroxine / Q000494:pharmacology; D014284:Triiodothyronine / Q000494:pharmacology
D004967:Estrogens; D007328:Insulin; D018969:Insulin-Like Growth Factor Binding Proteins; D014284:Triiodothyronine; D013739:Testosterone; D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I; D011388:Prolactin; D013006:Growth Hormone; D004247:DNA; D005934:Glucagon; D013974:Thyroxine