HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Rasmussen, M. H. Articles by Hilsted, J. Search for Related Content PubMed PubMed Citation Articles by Rasmussen, M. H. Articles by Hilsted, J.

Effects of short-term caloric restriction on circulating free IGF-I, acid-labile subunit, IGF-binding proteins (IGFBPs)-1–4, and IGFBPs-1–3 protease activity in obese subjects

Department of Endocrinology, Hvidovre Hospital, University of Copenhagen, DK-2650 Copenhagen, Denmark and ¹ Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, DK-2200 Copenhagen, Denmark

(Correspondence should be addressed to M H Rasmussen who is now at Langs Hegnet 52 B, Kongens Lyngby DK-2800, Denmark; Email: mhr{at}dadlnet.dk)

Objective: Decreased levels of GH and total IGF-I have been reported in obesity. It has been hypothesized that increased free (biologically active) IGF-I levels generated from IGF-binding protein (IGFBP) protease activity could be the mechanism for the low GH release in dieting obese subjects. However, no published data exist on free IGF-I levels, acid labile subunit (ALS), or IGFBP protease activity in relation to GH release during a hypocaloric diet. The main purpose of this study was to determine free IGF-I, ALS, IGFBPs-1–4, and IGFBPs-1–3 protease activity in relation to 24-h GH release before and after a short-term very low-calorie diet (VLCD).

Design: Six obese subjects before weight loss, five after an average weight loss of 36.1 kg, and five age-and sex-matched lean controls underwent a 4-day VLCD. All subjects were studied on two occasions, once during normal basic diet and again during the last day of the VLCD (1.6 MJ).

Methods: Free IGF-I was determined by a non-competitive immunoradiometric assay.

Results: Free IGF-I levels decreased in concert with increased ALS and unchanged blunted GH release after a VLCD in the obese subjects. IGFBPs-1–3 proteolytic activity was found to be unchanged by hypocaloric diet in all groups.

Conclusions: We conclude that free IGF-I decreases after a short-term hypocaloric diet in obese subjects with no concomitant change in 24-h GH release. Circulating free IGF-I per se cannot be the main mechanism of the attenuated GH release in dieting obese subjects.