Estrogen regulation of growth hormone action.

• GH plays a pivotal role in regulating body growth and development, which is modulated by sex steroids. A close interplay between estrogen and GH leads to attainment of gender-specific body composition during puberty. The physiological basis of the interaction is not well understood. Most previous studies have focused on the effects of estrogen on GH secretion. There is also strong evidence that estrogen modulates GH action independent of secretion. Oral but not transdermal administration of estrogen impairs the metabolic action of GH in the liver, causing a fall in IGF-I production and fat oxidation. This results in a loss of lean tissue and a gain of body fat in postmenopausal women and an impairment of GH effect in hypopituitary women on GH replacement. The negative metabolic sequelae are potentially important because of the widespread use of oral estrogen and estrogen-related compounds. Estrogen affects GH action at the level of receptor expression and signaling. More recently, estrogen has been shown to inhibit Janus kinase/signal transducer and activator of transcription signaling by GH via the induction of suppressor of cytokine signaling-2, a protein inhibitor for cytokine signaling. This represents a novel paradigm of steroid regulation of cytokine receptors and is likely to have significance for a diverse range of cytokine function.

Nyckelord

Animals

Body Composition

Carrier Proteins

physiology

Cytokines

physiology

Estrogens

pharmacology

physiology

therapeutic use

Female

Growth

Growth Hormone

physiology

Homeostasis

Humans

Insulin-Like Growth Factor I

physiology

Male

Receptors

Cytoplasmic and Nuclear

physiology

Receptors

Estrogen

physiology

Receptors

Somatotropin

physiology

Signal Transduction

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)