Effects of Estrogen and Sex Difference on Secretion of Human Growth Hormone1

Frantz, Andrew G.; Rabkin, Mitchell T.

doi:10.1210/jcem-25-11-1470

Cited by 469 publications

(143 citation statements)

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“…Although estrogens are highly effective in blocking the sequelae of GH overproduction in acromegaly, it has been shown that they actually stimulate GH secretion in humans (35). Hence, how can estrogens slow growth while increasing GH?…”

Section: Discussionmentioning

confidence: 99%

Interaction between malnutrition and ovarian hormones on the systemic IGF-I axis

Goya

García‐Segura²,

Ramos³

et al. 2002

European Journal of Endocrinology

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Objective: In malnutrition both the GH -IGF and reproductive axes are greatly affected. Because the actions of IGF and sex steroids are inter-dependent in many tissues, we have examined how ovariectomy modulates the response of the systemic IGF system to undernutrition. Design and methods: Peripubertal (30 days of age) female rats were either sham operated or ovariectomized. Five days later half of each group was submitted to a protein-caloric restriction diet. All rats were killed at 60 days of age. Results: Growth was decreased in all rats submitted to calorie restriction and this was consistent with a decrease in circulating IGF-I concentrations and liver IGF-I mRNA expression. While in normally fed rats ovariectomy had no significant effect on serum IGF-I concentrations, ovariectomized and underfed rats had significantly higher levels than intact underfed rats. In undernourished rats, serum IGF-binding proteins (IGFBP)-1, -2 and -3 concentrations were significantly reduced and this was not modified by ovariectomy. In contrast, liver mRNA concentrations of IGFBP-1 and -2 were increased and IGFBP-3 unchanged in intact undernourished animals, suggesting that undernutrition could be affecting the proteolysis of these binding proteins, and this response was significantly modulated by ovariectomy. Conclusion: These results indicate that the presence of circulating ovarian hormones significantly affects the response of the IGF system to undernutrition.

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Section: Discussionmentioning

confidence: 99%

Interaction between malnutrition and ovarian hormones on the systemic IGF-I axis

Goya

García‐Segura²,

Ramos³

et al. 2002

European Journal of Endocrinology

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“…Serum levels of the sex steroids, growth hormone (GH), and insulin-like growth factor I (IGF-I) are known to increase during puberty, but the interaction between the gonadal steroids and the GH-IGF-I axis has not been elucidated. Both experimental and clinical evidence indicates that the increased steroid secretion at puberty has an indirect effect on the skeletal tissues and that this effect is GH-dependent (Franz & Rabkin 1965). Estrogen stimulates the release of GH from the pituitary, thereby increasing serum IGF-I levels.…”

Section: Introductionmentioning

confidence: 99%

The aromatase inhibitor letrozole increases epiphyseal growth plate height and tibial length in peripubertal male mice

Eshet

Maor²,

Ari³

et al. 2004

Journal of Endocrinology

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Sex hormones may influence longitudinal growth, either indirectly, by affecting the growth-hormone-insulin-like growth factor I (IGF-I) axis, or directly, by affecting changes within the epiphyseal growth plate (EGP). The aim of the present study was to investigate the effects of letrozole, an aromatase inhibitor, on longitudinal growth and changes in the EGP in vivo. Eighteen peripubertal male mice were divided into three groups. The first group was killed at baseline, the second was injected with letrozole (Femara) s.c., 2 mg/kg body weight/day, for 10 days, and the third was injected with the vehicle alone. Serum testosterone levels were found to be significantly higher in the treated group than in the controls. Letrozole induced a significant increase in body weight, tail length and serum growth hormone level, but had no significant effect on the level of serum IGF-I. On histomorphometric study, there was a significant increase (12%) in EGP height in the treated animals compared with controls. Immunohistochemistry showed a 3·4-fold letrozole-induced increase in the proliferation of the EGP chondrocytes, as estimated by the number of proliferation cell nuclear antigen-stained cells, and a decrease in the differentiation of the EGP chondrocytes, as estimated by type X collagen staining. Letrozole did not interfere with type II collagen levels. The study group also showed a twofold increase in the number of IGF-I receptor-positive cells compared with controls. In conclusion, the aromatase inhibitor, letrozole, appears to increase the linear growth potential of the EGP in mice.

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“…Sixteen non-insulin dependent diabetic patients (mean age 52.8, range 32-69 years), non obese, having moderate untreated hypertension, were studied. Only males were selected because of the spontaneous GH increase in women during the menstrual cycle (Frantz & Rabkin, 1965). All patients were treated by diet + biguanides and well controlled (HbA1 < 10%, Kit Biorad Richmond, California).…”

mentioning

confidence: 99%