Postnatal catch-up growth induced by growth hormone and insulin-like growth factor-I in rats with intrauterine growth retardation caused by maternal protein malnutrition.
In this study, we examined the effects of exogenous IGF-I and GH on postnatal growth of rat pups with intrauterine growth retardation due to gestational protein restriction. From birth until weaning (d 23), pups born from dams fed ad libitum a low (5% casein; P5 pups) or a normal protein diet (20% casein; P20 controls) were cross-fostered to well nourished lactating dams. On d 2, the litters (n = 6/dietary group) were reduced in size to 6 pups, and littermates received, through postnatal d 23, two daily s.c. injections of bovine GH (2.5 microg/g of body weight (BW)/day), human IGF-I (1.8 microg/g of BW/day), or saline. At birth, BW and tail length (TL) of P5 pups were markedly decreased (to 72 and 70% of controls, respectively; p < 0.001). Despite food rehabilitation, stunting of body growth was still apparent on d 23 in the saline-injected P5 rats (BW and TL: 76 and 83% of age-matched saline-injected controls; p < 0.01). Serum IGF-I (-51%; p < 0.001) and weight of liver, heart, kidney, brain, and thymus (-13 to -35%; p < 0.01) were also reduced. Administration of GH in P5 rats raised their serum IGF-I (1-fold) to levels observed in saline-injected controls, and restored normal BW and TL (94 and 98% of controls, respectively), and organ weight (91-107% of those of controls). Injections of IGF-I in P5 rats increased after 1 h their serum IGF-I to levels 3 times greater than in saline-injected controls, and resulted in normalization of BW and TL (94 and 96% of controls), and organ weight (92-111% of controls). In P20 controls, 3-wk GH and IGF-I injections significantly increased serum IGF-I (0.6- and 2-fold increases, respectively), BW (14 and 11%), TL (12 and 11%), and organ weight (+10 to 30%) compared with saline-injected rats (p < 0.01). We conclude that under conditions of adequate nutrition, both GH and IGF-I may equally promote postnatal catch-up growth in rats with intrauterine growth retardation caused by gestational protein malnutrition.
Muaku
S M
SM
Unité de Diabétologie et Nutrition, University of Louvain School of Medicine, Brussels, Belgium.
Thissen
J P
JP
Gerard
G
G
Ketelslegers
J M
JM
Maiter
D
D
D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development*; D000833:Animals, Suckling; D018753:Diet, Protein-Restricted; D005314:Embryonic and Fetal Development / Q000502:physiology; D005260:Female; D005317:Fetal Growth Retardation / Q000209:etiology* / Q000503:physiopathology; D005865:Gestational Age; D006128:Growth / Q000187:drug effects*; D013006:Growth Hormone / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000494:pharmacology*; D008099:Liver / Q000737:chemistry / Q000187:drug effects / Q000254:growth & development; D008297:Male; D008431:Maternal-Fetal Exchange; D009929:Organ Size / Q000187:drug effects / Q000502:physiology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011502:Protein-Energy Malnutrition / Q000150:complications*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone