There is now wide consensus that, within an appropriate clinical context, GH deficiency (GHD) in adults must be shown biochemically by provocative testing of GH secretion and that appropriate cut-off limits have to be defined for each provocative test. Insulin-induced hypoglycemia (ITT) is indicated as the test of choice, and severe GHD, to be treated with recombinant human GH replacement, is d...

An increased dietary load of cholesterol (ch) and saturated fat increases serum low density lipoprotein ch (LDL-ch) levels. GH therapy in GH-deficient adults decreases serum LDL-ch levels. In the rat, GH is important for resistance to dietary cholesterol in terms of serum cholesterol levels. The aim of this study was to investigate the influence of GH on the effects of an increase in the intake...

The long-term effects of growth hormone (GH) are mediated through coordinated changes in gene expression that are the outcome of interactions between hormone-activated signal transduction pathways and specific feedback loops. Recent studies in mice have implicated the transcription factor STAT5b as part of the GH-regulated somatic growth pathway, because mice lacking this protein showed diminis...

GH stimulates the tyrosine phosphorylation of various cellular polypeptides, including the GH receptor itself, in an early part of the intracellular response. Some of these phosphorylations are catalyzed by a GH receptor-associated kinase identified as JAK2, a member of the Janus family of tyrosine kinases. In cultured cells, GH stimulates the tyrosine phosphorylation of insulin receptor substr...

Fasting causes a state of GH resistance responsible for low circulating IGF-I levels. To investigate whether this resistance may result from alterations in the GH signaling pathway, we determined the effects of fasting on the GH transduction pathway in rat liver. Forty-eight-hour fasted or fed male rats were injected with recombinant rat GH via the portal vein. Liver was removed 0 and 15 min af...

In human studies, the principal determinant of serum leptin concentrations is fat mass (FM), but lean mass (LM) also has a significant negative influence. GH treatment in GH deficiency (GHD) alters body composition, increasing LM and decreasing FM, and thus would be expected to alter leptin concentrations. We have therefore examined the acute and chronic effects of GH on serum leptin in 12 elde...

In their study published in this issue, Iglesias et al. give the vascular effects, independent of GH release, has been first evidence that ghrelin is synthesized and secreted by cardiomyocytes. Ghrelin is a 28-amino acid peptide containing an n-octanoyl modification at serine 3. It acts on the pituitary and hypothalamus to stimulate growth hormone (GH) release, food intake, and adiposity. It ha...

Sustained administration of growth hormone (GH) to human subjects with NH(4)Cl-induced chronic metabolic acidosis (CMA) results in a large (4.5+/-0.5 mmol/l) increase in the plasma HCO(3-) concentration, as mediated by a large increase in renal net acid excretion. The renal mechanism(s) responsible for the potent stimulation of renal hydrogen ion secretion by GH remain to be elucidated. Accordi...

Therapeutic use of growth hormone (GH) in the United States generally has been restricted to GHdeficient children who, with their families, agree to participate in research. The limited supply and the considerable expense of commercially prepared GH have restricted the number of children who have received such therapy. As the medical community and public become more aware of the therapeutic pot...

the mrna expression of growth hormone (gh) gene in early development stages of siberian sturgeon was investigated using rt-pcr method. samples were collected from unfertilized eggs up to 50 days post hatched (dph) larvae in 11 different times. ribosomal protein l6 (rpl6) transcripts were used as the internal standard during quantification of gh mrna expression. the results showed that the gh mr...