Leptin levels are strongly correlated with those of GH-binding protein in prepubertal children

Abstract

Objective: Nutritional status is an important determinant of growth, and previous studies have indicated that this is due, at least in part, to an increased target-tissue sensitivity to GH. An attractive candidate for mediating this effect is leptin, a hormone secreted by the adipose tissue. The aim of this study was to investigate if there was a connection between GH-binding protein (GHBP) and leptin. Design and Methods: We investigated the relationship between serum levels of leptin and those of GHBP in 229 prepubertal children. These included 107 healthy children with normal GH secretion, 55 GHdeficient (GHD) children and 55 children born small for gestational age (SGA) sampled on one occasion for GHBP and leptin, and 12 healthy children followed longitudinally at monthly intervals for 1 year. Results: In the healthy children and in those born SGA, the serum concentration of GHBP was positively correlated with that of leptin (r ¼ 0:65, P < 0:001; r ¼ 0:74, P < 0:001 respectively). There was no correlation between GHBP and leptin in the group of children with GHD (r ¼ 0:27, not significant). This means that leptin alone explained 42% of the variation of GHBP in the healthy group and 55% in the SGA group. The correlation remained after adjustment for body mass index and age in the healthy children (r ¼ 0:57, P < 0:0001, r 2 ¼ 0:33) and for children born SGA (r ¼ 0:74, P < 0:0001, r 2 ¼ 0:55). There was a positive correlation between the intra-individual monthly changes in GHBP and changes in leptin respectively, in the 12 healthy children followed longitudinally, the mean of the correlation coefficients was 0:38 (median ¼ 0:29; range 0:03 to 0:86; P < 0:05). Conclusions: There was a highly significant correlation between serum levels of leptin and those of GHBP, except in children with GHD. The possibility that leptin could mediate the effects of body fat mass on GH sensitivity, therefore, merits further investigation. European Journal of Endocrinology 137 68-73

Effects of pair-feeding and growth hormone treatment on obese transgenic rats

“…However, pair-feeding did not affect serum FFA levels in the transgenic rats. One possible explanation for this result could be that there was no alteration of WAT mass in pair-fed transgenic rats, because it has been shown that circulating FFA concentration is well correlated with adipose tissue mass (15). On the other hand, although hGH treatment reduced fat accumulation in transgenic animals, it did not significantly affect serum FFA levels.…”

Circulating IGF binding protein-1 is inversely associated with leptin in non-obese men and obese postmenopausal women

“…For example, intracerebroventricular administration of leptin antiserum reduced GH secretion in rats (11) and GH administration to GH-deficient humans has been found to reduce leptin levels, probably through reduced amount of body fat mass (13). Leptin could also influence GH effects in the periphery through association with the GH-binding protein and the IGFBPs (12,33).…”

Effects of pulsatile secretion of growth hormone (GH) on fat deposition in human GH transgenic rats

“…In obese individuals, however, high plasma leptin levels do not induce anorexic responses theoretically expected and this inconsistency has led to the concept of leptin resistance Bjarnason et al 1997). In obese GHD human adults, an increased circulating leptin is observed (Bjarnason et al 1997;Fisker et al 1997;Janssen et al 1997), therefore we analysed our obese and GH-deficient hGH transgenic animals to determine whether or not they were leptin-resistant. As mentioned already, the transgenic rats have much increased leptin levels, despite which, food intake is enhanced and locomotor activity suppressed.…”