Hormonal Regulation of Rat Hypothalamic Neuropeptide mRNAs: Effect of Hypophysectomy and Hormone Replacement on Growth-Hormone-Releasing Factor, Somatostatin and the Insulin-Like Growth Factors

1991 ◽  
Vol 53 (3) ◽  
pp. 298-305 ◽  
Author(s):  
Teresa L. Wood ◽  
Michael Berelowitz ◽  
Marie C. Gelato ◽  
Charles T. Roberts, Jr. ◽  
Derek LeRoith ◽  
...  
1986 ◽  
Vol 113 (1_Suppl) ◽  
pp. S124
Author(s):  
U. VETTER ◽  
J. ZAPF ◽  
W. HEIT ◽  
E. HEINZE ◽  
R.E. FROESCH ◽  
...  

1995 ◽  
Vol 132 (3) ◽  
pp. 313-319 ◽  
Author(s):  
P Ravn ◽  
K Overgaard ◽  
EM Spencer ◽  
C Christiansen

Ravn P, Overgaard K, Spencer EM, Christiansen C. Insulin-like growth factors I and II in healthy women with and without established osteoporosis. Eur J Endocrinol 1995;132:313–9. ISSN 0804–4643 We measured serum concentrations of insulin-like growth factors I and II (IGF-I and IGF-II) by radioimmunoassay in 107 healthy women aged 28–78 years and in 116 women with established osteoporosis. The women with established osteoporosis were randomized to a 1-year double-blind, placebo-controlled treatment with continuous estrogen/progestogen, anabolic steroids, salmon calcitonin or placebo and the IGFs were measured every 6 months. Women less than 35 years of age had 29% higher levels of IGF-I (p < 0.001) as compared to women above that age. For women more than 35 years of age, we found no correlation between IGF-I and age (r = 0.02). Correspondingly, we found no significant changes in serum IGF-I in 10 women, who were followed with serial measurements of IGFs every 3 months from 2 years before to 1 year after menopause; IGF-II revealed no correlation with age (r = 0.04). In the group of 116 women with established osteoporosis, IGF-I was 30% lower (p < 0.01) as compared to a group of 19 height-, weight- and age-matched nonfractured women (mean age 64 years). The IGF-II levels were equal in the two groups. Over the 1-year therapeutic intervention period, an increase in IGF-I of 13–15% (p < 0.05) was seen in the nandrolone decanoate-treated group. The same tendency was seen for hormone replacement therapy, although it was not significant. In conclusion, the serum level of IGF-I is high in young women, when peak bone mass is attained, and low in postmenopausal women with established osteoporosis. Pernille Ravn, Center for Clinical & Basic Research, Ballerup Byvej 222, DK-2750 Ballerup, Denmark


1996 ◽  
Vol 21 (4) ◽  
pp. 236-250 ◽  
Author(s):  
Jamie MacGregor ◽  
Wade S. Parkhouse

The role of the insulin-like growth factors I and II (IGF-I and IGF-II), previously known as the somatomedins, in general growth and development of various tissues has been known for many years. Thought of exclusively as endocrine factors produced by the liver, and under the control of growth hormone, the somatomedins were known as the intermediaries by which growth hormone exerted its cellular effects during tissue growth and maturation. Eventually it was discovered that virtually every tissue type is capable of autocrine production of the IGFs, and their involvement in skeletal muscle tissue repair and regeneration became apparent. Recent advances in technology have allowed the characterisation of many of the different growth factors believed to play a role in muscle regeneration, and experimental manipulations of cells in culture have provided insight into the effects of the various growth factors on the myoblast. This paper explores the potential role of the IGFs in skeletal muscle regeneration. A critical role of IGF-II in terminal differentiation of proliferating muscle precurser cells following injury is proposed. Key words: growth factors, myogenesis, skeletal muscle regeneration


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