Salivary insulin-like growth factor-I originates from local synthesis

1992 ◽  
Vol 135 (1) ◽  
pp. 85-NP ◽  
Author(s):  
J. Ryan ◽  
T. Mantle ◽  
S. McQuaid ◽  
D. C. Costigan
Keyword(s):  
Growth Factor ◽  
Gel Chromatography ◽  
Insulin Like Growth Factor ◽  
Sprague Dawley ◽  
Local Synthesis ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I ◽  
Rat Parotid ◽  
Dependent Growth

ABSTRACT Insulin-like growth factor-I (IGF-I) is a GH-dependent growth factor found in its highest concentrations in plasma. It is also measurable in saliva. The origins of salivary IGF-I concentrations were studied. Intracardial administration of Sprague–Dawley rats with 125I-labelled IGF-I and subsequent analysis of plasma and saliva samples by exclusion gel chromatography and SDS-PAGE, followed by autoradiography, demonstrated the apparent inability of IGF-I to cross from the plasma pool through to saliva. 125I-Labelled IGF-I was not chromatographed immediately before injection, resulting in administration of free iodide along with the iodinated peptide. This free iodide was demonstrable in saliva, indicating that movement of substances from plasma to saliva was measurable using the levels of 125I activity administered. Free iodide in saliva was not contributed to by 125I-labelled IGF-I degradation since 125I-labelled IGF-I was shown to be stable in saliva over 24 h. These data indicated that IGF-I in saliva is produced locally. Identification of a 4·7 kb IGF-I mRNA transcript in rat parotid salivary gland was consistent with IGF-I synthesis within that tissue. Journal of Endocrinology (1992) 135, 85–90

scholarly journals The Effect of Capsaicin on IGF-I and IGF-IR Expression in Ovarian Granulosa Cells

2020 ◽  
Vol 71 (1) ◽  
pp. 1977
Author(s):  
S. GULER ◽  
Β. ZIK
Keyword(s):  
Growth Factor ◽  
Granulosa Cells ◽  
Ovarian Development ◽  
Ovary Development ◽  
Insulin Like Growth Factor ◽  
Sprague Dawley ◽  
Factor I ◽  
Ovarian Granulosa Cells ◽  
Igf I ◽  
Growth Factor I

Capsaicin (trans-8-methyl-N-vanillyl-6-noneadamide) is a pungent ingredient in red peppers from the Capsicum family. Insulin-like growth factor-I (IGF-I) is expressed in granulosa cells and has an important role in ovarian development. However, there are no data about the IGF-I expression in ovarian granulosa cells after capsaicin treatment. The aim of this study was to investigate the expression of IGF-I and its receptor (insulin-like growth factor-I receptor [IGF-IR]) in primary rat ovarian granulosa cells after low and high doses of capsaicin treatment. For this, granulosa cells were isolated and cultured from ovaries of 30-day-old female Sprague-Dawley rats. Granulosa cell plates were divided into four groups as cell control (C), vehicle control (V), and 50 μM and 150 μM capsaicin groups. In experimental groups, granulosa cells were exposed to capsaicin for 24 hours and immunocytochemistry was performed afterwards using anti-IGF-I and anti-IGF-IR antibodies. Both IGF-I and IGF-IR expressions were found to be significantly increased in parallel to the capsaicin doses. Elevated levels of IGF-I may be a risk factor for ovarian development. Because of the crucial role of IGF-I in ovary development, capsaicin treatment can be effective on follicular development and/or disorders characterized by high IGF-I levels.

Release of insulin-like growth factor I by the sheep placenta in vitro

1991 ◽  
Vol 3 (4) ◽  
pp. 379 ◽  
Author(s):  
J Falconer ◽  
JJ Davies ◽  
HP Zhang ◽  
R Smith
Keyword(s):  
Molecular Weight ◽  
Growth Factor ◽  
Binding Protein ◽  
Basal Plate ◽  
Gel Chromatography ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I ◽  
Villous Tissue

This study has utilized a tissue perifusion system to examine the release of insulin-like growth factor I (IGF I) from different regions of the sheep placenta at two stages of gestation. Placentae were obtained from ewes at either 116 +/- 7 (mean +/- s.e.) or 144 +/- 1.5 days of gestation and separated into the maternal basal plate or chorionic villous tissue. At both ages, the maternal basal plate tissue released approximately three times more IGF I than the chorionic villous tissue. No difference was found between the rate of release of IGF I from the maternal basal plate at 120 and 140 days of gestation, whereas the chorionic villous tissue released less IGF I later in gestation. Maternal basal plate tissue was less responsive to a depolarizing dose of KCl than was chorionic villous tissue at either age. After acid gel chromatography, perfusate from the basal plate had three peaks of IGF immunoreactivity (corresponding to binding protein, IGF I and a form with an intermediate molecular weight). In contrast, the chorionic villous tissue released only a form with a high molecular weight, corresponding to binding protein. These results demonstrate that the sheep placenta produced IGF I, that secretion varies between different placental zones which contain different cell types and that there are maturational changes in placental IGF I secretion. The IGFs may be involved in placental growth.

Insulin-like growth factor I in the dog: a study in different dog breeds and in dogs with growth hormone elevation

1984 ◽  
Vol 105 (3) ◽  
pp. 294-301 ◽  
Author(s):  
J. E. Eigenmann ◽  
D. F. Patterson ◽  
J. Zapf ◽  
E. R. Froesch
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Gel Chromatography ◽  
Insulin Like Growth Factor ◽  
Significant Drop ◽  
Factor I ◽  
Igf I ◽  
The Mean ◽  
Growth Factor I ◽  
The One

Abstract. A radioimmunoassay (RIA) devised for the measurement of human insulin-like growth factor I (IGF I) was employed for the measurement of canine IGF I. Canine IGF I was extracted from plasma specimens by gel chromatography. Columns were eluted with 1 m acetic acid and the fractions representing the 55 to 85% bed volume were pooled, lyophilized and reconstituted with assay buffer. Serial dilutions of canine IGF I from both normal and acromegalic dogs when added to the RIA system gave a similar displacement pattern of human [125I]IGF I as the one obtained by the addition of unlabelled human IGF I. The dose-response curve obtained by canine IGF I paralleled the one obtained by human IGF I. Logit-log transformation and least squares fitting resulted in straight line fitting of the standard curve between 0.039 and 5 ng IGF I added per tube. The within-assay coefficient of variation (CV) was 16.7% and the between-assay CV was 21.8%. Plasma IGF I concentrations in normal dogs appeared to be a function of body size. The concentrations were 36 ± 27 ng/ml in Cocker Spaniels, 87 ± 33 ng/ml in Beagles, 117 ± 34 ng/ml in Keeshonds, and 280 ± 23 ng/ml in German Shepherds (mean ± sem). The mean IGF I level in a group of dogs with growth hormone (GH) elevation was 700 ± 90 ng/ml. Though this group of dogs comprised both small and large dogs, the mean IGF I level significantly differed from the one found in German Shepherds, the largest breed studied (P < 0.01). IGF I levels in dogs with GH elevation were similarly elevated in both dogs exhibiting acromegaly and dogs exhibiting GH-diabetes, but no signs of acromegaly. In dogs with GH elevation, drop in GH levels was associated with a significant drop in IGF I levels.

Presence of insulin-like growth factor I but absence of the binding proteins in the bile of rats

1995 ◽  
Vol 268 (1) ◽  
pp. R266-R271
Author(s):  
W. Kong ◽  
A. F. Philipps ◽  
B. Dvorak ◽  
G. G. Anderson ◽  
M. Lake ◽  
...  
Keyword(s):  
Growth Factor ◽  
Binding Proteins ◽  
Gel Chromatography ◽  
Insulin Like Growth Factor ◽  
Adult Rats ◽  
Igf Binding Proteins ◽  
Factor I ◽  
Igf I ◽  
Dependent Inhibition ◽  
Growth Factor I

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 micrograms/day in the suckling and remained constant at 1.6-1.7 micrograms/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-I in bile may play an important role in the growth of the gastrointestinal tract, both in the suckling as well as later in life.

Kidney insulin-like growth factor-I mRNA levels are increased in postpubertal diabetic rats

1991 ◽  
Vol 129 (1) ◽  
pp. 5-10 ◽  
Author(s):  
L. A. Bach ◽  
J. L. Stevenson ◽  
T. J. Allen ◽  
G. Jerums ◽  
A. C. Herington
Keyword(s):  
Growth Factor ◽  
Northern Blotting ◽  
Diabetic Rats ◽  
Mrna Levels ◽  
Insulin Like Growth Factor ◽  
Sprague Dawley ◽  
Factor I ◽  
Igf I ◽  
Renal Enlargement ◽  
Growth Factor I

ABSTRACT Diabetes-associated renal enlargement is more marked in postpubertal than prepubertal rats, and in the postpubertal rat, is associated with increased kidney insulin-like growth factor-I (IGF-I) levels for the first 2 days. In order to determine whether local IGF-I production is the cause of this increase in tissue levels, IGF-I mRNA levels were determined in pre- and postpubertal Sprague–Dawley rats made diabetic with streptozotocin (STZ) and in control rats. RNA was extracted from kidneys and livers of rats at 0 h, 6 h, 12 h and days 1, 2, 3 and 7 after STZ injection. After Northern blotting and hybridization with an oligonucleotide probe complementary to an E domain of the IGF-I cDNA, four distinct bands (7·4, 4·8, 1·8 and 1·0 kb) were found. Densitometric analyses of the most prominent bands (7·4 and 1·0 kb), after normalization for 18S ribosomal RNA content, revealed a 50–100% increase in the kidneys of postpubertal diabetic rats compared with postpubertal controls 12 h after STZ injection (P < 0·05, diabetes vs control). Between days 2 and 7, kidney IGF-I mRNA levels in postpubertal diabetic rats fell to approximately 50% of control levels (P < 0·05, diabetes vs control). In contrast, kidney IGF-I mRNA levels in the prepubertal diabetic rats remained unchanged over the 7 days. Liver IGF-I mRNA levels did not rise during the first 24 h and fell to approximately 60% of control levels by day 7 in both pre- and postpubertal diabetic rats (P < 0·05, diabetes vs control). Increased local IGF-I production may underlie the initiation of renal enlargement associated with diabetes mellitus. Journal of Endocrinology (1991) 129, 5–10

Sign in / Sign up

Export Citation Format

Share Document