Specific Binding of Growth Hormone by Rat Adipocytes*

Fagin, Katherine D.; Lackey, S.L.; Reagan, Charles R.; DiGirolamo, Mario

doi:10.1210/endo-107-2-608

Cited by 88 publications

(33 citation statements)

References 27 publications

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“…In mammals, direct effects of GH or the presence of GH receptors was found in tissues implicated in growth function, such as fat (Fagin et al, 1980;Gavin et al, 1982;Digirolamo et al, 1986), skin (Murphy et al, 1983), cartilage (Eden et al, 1983), and muscle (Daughaday, 1977). Saturable GH binding was also found in muscle of rainbow trout, masu salmon, and char (Salvelinus pluvius) (Ikuta et al, 1989).…”

Section: Discussionmentioning

confidence: 99%

Presence of specific growth hormone binding sites in rainbow trout (Oncorhynchus mykiss) tissues: Characterization of the hepatic receptor

Yao

Niu

Gac

et al. 1991

General and Comparative Endocrinology

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Section: Discussionmentioning

confidence: 99%

Presence of specific growth hormone binding sites in rainbow trout (Oncorhynchus mykiss) tissues: Characterization of the hepatic receptor

Yao

Niu

Gac

et al. 1991

General and Comparative Endocrinology

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“…Human adipocytes, like rat adipocytes, are target cells for GH [2-71. However, only the insulinantagonistic effect of hGH has been demonstrated in human fat cells [5] while rat fat cells respond with both an initial insulin-like and a subsequent insulin-antagonistic effect [6,7].…”

Section: Discussion Hgh (= 100%)mentioning

confidence: 99%

Specific binding of human growth hormone but not insulin‐like growth factors by human adipocytes

et al. 1986

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Binding of human GH (hGH) and insulin-like growth factors I and II (IGFI and II) to isolated human adipocytes from adult subjects was studied. Binding equilibrium for hGH at 24°C was reached at 120 min and half-maximal specific binding at 6-8 ng/ml. Apparent K, was 2.1 x log M-l and B,,, 7.3 x 10 -ii M/lo6 cells. The human fat cell growth hormone receptor recognized neither bovine, ovine or rat GH nor human prolactin or placental lactogen. No specific receptors for human IGFII could be demonstrated.Thus, human adipocytes do not possess IGF receptors but have specific GH receptors which recognize hGH but not GH from lower species. Growth hormone InsulinInsulin-like growth factor Adipocyte

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“…54 IGF-I mRNA and IGF-I peptide levels in WAT are regulated by GH, 53 through speci®c receptors on adipocytes. 55 It appears unlikely, however, that IGF-I from WAT contributes to the circulating IGF-I concentrations, and hence to the control of GH release. In fact, WAT does not release in vitro substantial amounts of IGF-I, 53 while the secretion rate of IGF-I from isolated rat livers fully accounts for the serum IGF-I levels normally found.…”

Section: Gh In Obesity M Scacchi Et Almentioning

confidence: 99%

Growth hormone in obesity

1999

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Growth hormone (GH) secretion, either spontaneous or evoked by provocative stimuli, is markedly blunted in obesity. In fact obese patients display, compared to normal weight subjects, a reduced half-life, frequency of secretory episodes and daily production rate of the hormone. Furthermore, in these patients GH secretion is impaired in response to all traditional pharmacological stimuli acting at the hypothalamus (insulin-induced hypoglycaemia, arginine, galanin, L-dopa, clonidine, acute glucocorticoid administration) and to direct somatotrope stimulation by exogenous growth hormone releasing hormone (GHRH). Compounds thought to inhibit hypothalamic somatostatin (SRIH) release (pyridostigmine, arginine, galanin, atenolol) consistently improve, though do not normalize, the somatotropin response to GHRH in obesity. The synthetic growth hormone releasing peptides (GHRPs) GHRP-6 and hexarelin elicit in obese patients GH responses greater than those evoked by GHRH, but still lower than those observed in lean subjects. The combined administration of GHRH and GHRP-6 represents the most powerful GH releasing stimulus known in obesity, but once again it is less effective in these patients than in lean subjects. As for the peripheral limb of the GH ± insulin-like growth factor I (IGF-I) axis, high free IGF-I, low IGF-binding proteins 1 (IGFBP-1) and 2 (IGFBP-2), normal or high IGFBP-3 and increased GH binding protein (GHBP) circulating levels have been described in obesity. Recent evidence suggests that leptin, the product of adipocyte speci®c ob gene, exerts a stimulating effect on GH release in rodents; should the same hold true in man, the coexistence of high leptin and low GH serum levels in human obesity would ®t in well with the concept of a leptin resistance in this condition. Concerning the in¯uence of metabolic and nutritional factors, an impaired somatotropin response to hypoglycaemia and a failure of glucose load to inhibit spontaneous and stimulated GH release are well documented in obese patients; furthermore, drugs able to block lipolysis and thus to lower serum free fatty acids (NEFA) signi®cantly improve somatotropin secretion in obesity. Caloric restriction and weight loss are followed by the restoration of a normal spontaneous and stimulated GH release. On the whole, hypothalamic, pituitary and peripheral factors appear to be involved in the GH hyposecretion of obesity. A SRIH hypertone, a GHRH de®ciency or a functional failure of the somatotrope have been proposed as contributing factors. A lack of the putative endogenous ligand for GHRP receptors is another challenging hypothesis. On the peripheral side, the elevated plasma levels of NEFA and free IGF-I may play a major role. Whatever the cause, the defect of GH secretion in obesity appears to be of secondary, probably adaptive, nature since it is completely reversed by the normalization of body weight. In spite of this, treatment with biosynthetic GH has been shown to improve the body composition and the metabolic ef®cacy of lean body mass in obese pa...

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Specific Binding of Growth Hormone by Rat Adipocytes*

Cited by 88 publications

References 27 publications

Presence of specific growth hormone binding sites in rainbow trout (Oncorhynchus mykiss) tissues: Characterization of the hepatic receptor

Presence of specific growth hormone binding sites in rainbow trout (Oncorhynchus mykiss) tissues: Characterization of the hepatic receptor

Specific binding of human growth hormone but not insulin‐like growth factors by human adipocytes

Growth hormone in obesity

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