scholarly journals Exogenous Insulin-Like Growth Factor-I Increases Weight Gain in Intrauterine Growth-Retarded Neonatal Pigs

1997 ◽  
Vol 42 (2) ◽  
pp. 201-207 ◽  
Author(s):  
P A Schoknecht ◽  
S Ebner ◽  
A Skottner ◽  
D G Burrin ◽  
T A Davis ◽  
...  
1989 ◽  
Vol 122 (1) ◽  
pp. 79-86 ◽  
Author(s):  
D. J. Flint ◽  
M. J. Gardner

ABSTRACT Treatment of rats for 24 h on day 2, 10 or 20 of age with a specific antiserum to rGH (anti-(rGH)), GH, bromocriptine (CB-154) or prolactin failed to influence body weight gain or serum concentrations of insulin-like growth factor-I (IGF-I). On day 28 of age, however, anti-(rGH) completely inhibited body weight gain and markedly reduced circulating IGF-I concentrations, effects which were completely prevented by exogenous ovine GH (oGH). When administered to control rats on day 28 oGH caused supranormal weight gain and serum IGF-I concentrations. These results suggested that GH does not play a significant role in growth or regulation of serum IGF-I until after day 20 of age. By contrast, when anti-(rGH) was given for 4 consecutive days beginning on day 2 of life, body weight gain was reduced within 48 h and remained so until at least 28 days of age. Tail length was also significantly reduced. The effect was due to inhibition of GH effects since serum GH concentrations were low and exogenous GH prevented the effect. Inhibition of growth during the first 14 days of life occurred in the absence of any effect on serum IGF-I although by 21 days of age serum IGF-I was considerably lower than in control rats. The prolonged reduction in growth after treatment has stopped appeared to be due to a cytotoxic effect on the pituitary gland since pituitary weight and GH but not prolactin content were significantly decreased. The data are consistent with the hypothesis that in the neonate GH may be processed in serum so that a proportion of it is not recognized by an antiserum to pituitary GH. It would appear that inhibition of GH secretion reduces growth rate by at least 30–40% up to 14 days of age, 50% by 21 days of age and completely by 28 days. Effects of GH on growth could not be fully explained by regulation of serum IGF-I concentrations. Journal of Endocrinology (1989) 122, 79–86


2002 ◽  
Vol 87 (6) ◽  
pp. 587-593
Author(s):  
Dunshea F.R.* ◽  
C.S. Chung ◽  
P.C. Owens ◽  
J.F. Ballard ◽  
P.E. Walton

1990 ◽  
Vol 124 (3) ◽  
pp. 381-386 ◽  
Author(s):  
M. J. Gardner ◽  
D. J. Flint

ABSTRACT Treatment of neonatal rats on days 2–5 with antibodies against rat GH (rGH) markedly reduced body weight gain and serum concentrations of insulin-like growth factor-I for 6–8 weeks in both females and males, after which weight gain normalized without evidence of catch-up growth. There were no significant effects on serum prolactin, tri-iodothyronine or corticosterone. Testis and ovarian weights were reduced, although only in proportion to body size. In females, but not males, the treated rats, though lighter, had increased fat deposition in the parametrial depot. Pituitary weight was considerably reduced over 100 days later, as was the pituitary content of GH, but not prolactin. The response to GH-releasing factor of both male and female rats was also greatly reduced at this time. Taken together with the fact that these rGH antibodies can bind directly to somatotrophs, we propose that the long-term effects of the antibodies are induced by specific somatotroph destruction. Journal of Endocrinology (1990) 124, 381–386


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