Abstract
Whereas insulin-like growth factor I (IGF-I) has been found in various body fluids from different species, the presence or absence of IGF and associated binding proteins (IGFBPs) in bile has not been clearly defined. Bile concentration of IGF-I was measured in this study and found to be highest in the neonate and lowest in adult rats (133 ± 15.9, 79.4 ± 10.5, 45.3 ± 12.7 ng/ml (mean ± SE) in 12-day-old, 33-day-old, and adult rats, respectively]. When bile delivery rates of IGF-I (i.e., the product of IGF-I concentration in bile and the biliary flow rate) were calculated, IGF-I delivery was highest in weanling rats (469 pg · h-1 · g body wt-1). When expressed as amount of IGF-I in bile delivered per day, however, delivery rates rose from 0.2 μg/day in the suckling and remained constant at 1.6-1.7 μg/day in both weanling and adult animals. Bile samples exposed to a placental membrane IGF receptor preparation showed significant dose-dependent inhibition of binding of native IGF-I. Because no IGF binding proteins were identified by Western ligand blot or by Sephadex gel chromatography, the results suggest the presence of biologically significant quantities of bioactive IGF-I in bile. We speculate that IGF-1 in bile may play an important role in the growth of the gastrointestinal tract, both in the suckling as well as later in life.
| Original language | English (US) |
|---|---|
| Journal | American Journal of Physiology - Regulatory Integrative and Comparative Physiology |
| Volume | 268 |
| Issue number | 1 37-1 |
| State | Published - 1995 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Physiology
- Agricultural and Biological Sciences(all)
Cite this
Presence of insulin-like growth factor I but absence of the binding proteins in the bile of rats. / Kong, W.; Philipps, Anthony F; Dvorak, B.; Anderson, G. G.; Lake, M.; Koldovsky, O.
In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 268, No. 1 37-1, 1995.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Presence of insulin-like growth factor I but absence of the binding proteins in the bile of rats
AU - Kong, W.
AU - Philipps, Anthony F
AU - Dvorak, B.
AU - Anderson, G. G.
AU - Lake, M.
AU - Koldovsky, O.
PY - 1995
Y1 - 1995
N2 - Whereas insulin-like growth factor I (IGF-I) has been found in various body fluids from different species, the presence or absence of IGF and associated binding proteins (IGFBPs) in bile has not been clearly defined. Bile concentration of IGF-I was measured in this study and found to be highest in the neonate and lowest in adult rats (133 ± 15.9, 79.4 ± 10.5, 45.3 ± 12.7 ng/ml (mean ± SE) in 12-day-old, 33-day-old, and adult rats, respectively]. When bile delivery rates of IGF-I (i.e., the product of IGF-I concentration in bile and the biliary flow rate) were calculated, IGF-I delivery was highest in weanling rats (469 pg · h-1 · g body wt-1). When expressed as amount of IGF-I in bile delivered per day, however, delivery rates rose from 0.2 μg/day in the suckling and remained constant at 1.6-1.7 μg/day in both weanling and adult animals. Bile samples exposed to a placental membrane IGF receptor preparation showed significant dose-dependent inhibition of binding of native IGF-I. Because no IGF binding proteins were identified by Western ligand blot or by Sephadex gel chromatography, the results suggest the presence of biologically significant quantities of bioactive IGF-I in bile. We speculate that IGF-1 in bile may play an important role in the growth of the gastrointestinal tract, both in the suckling as well as later in life.
AB - Whereas insulin-like growth factor I (IGF-I) has been found in various body fluids from different species, the presence or absence of IGF and associated binding proteins (IGFBPs) in bile has not been clearly defined. Bile concentration of IGF-I was measured in this study and found to be highest in the neonate and lowest in adult rats (133 ± 15.9, 79.4 ± 10.5, 45.3 ± 12.7 ng/ml (mean ± SE) in 12-day-old, 33-day-old, and adult rats, respectively]. When bile delivery rates of IGF-I (i.e., the product of IGF-I concentration in bile and the biliary flow rate) were calculated, IGF-I delivery was highest in weanling rats (469 pg · h-1 · g body wt-1). When expressed as amount of IGF-I in bile delivered per day, however, delivery rates rose from 0.2 μg/day in the suckling and remained constant at 1.6-1.7 μg/day in both weanling and adult animals. Bile samples exposed to a placental membrane IGF receptor preparation showed significant dose-dependent inhibition of binding of native IGF-I. Because no IGF binding proteins were identified by Western ligand blot or by Sephadex gel chromatography, the results suggest the presence of biologically significant quantities of bioactive IGF-I in bile. We speculate that IGF-1 in bile may play an important role in the growth of the gastrointestinal tract, both in the suckling as well as later in life.
UR - http://www.scopus.com/inward/record.url?scp=0028795302&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0028795302&partnerID=8YFLogxK
M3 - Article
C2 - 7840330
AN - SCOPUS:0028795302
VL - 268
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
SN - 1931-857X
IS - 1 37-1
ER -