Ralph Rabkin

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We analyzed expression of 81 normal muscle samples from humans of varying ages, and have identified a molecular profile for aging consisting of 250 age-regulated genes. This molecular profile correlates not only with chronological age but also with a measure of physiological age. We compared the transcriptional profile of muscle aging to previous(More)
Chronic renal failure (CRF) is associated with resistance to the growth-promoting and anabolic actions of growth hormone (GH). In rats with CRF induced by partial renal ablation, 7 days of GH treatment had a diminished effect on weight gain and hepatic IGF-1 and IGFBP-1 mRNA levels, compared with sham-operated pair-fed controls. To assess whether GH(More)
Resistance to growth hormone (GH) is a significant complication of advanced chronic renal failure. Thus while the circulating GH levels are normal or even elevated in uremia, resistance to the hormone leads to stunting of body growth in children and contributes to muscle wasting in adults. Insensitivity to GH is the consequence of multiple defects in the(More)
Cytokines consist of a large family of secreted proteins, including pro-inflammatory agents, growth hormone and erythropoietin, that utilize the Janus kinase (JAK) signal transducer and activator of transcription (STAT) signal transduction pathway to mediate many of their key physiologic and pathologic actions. These actions include cytokine-mediated(More)
When added to cultured opossum kidney cells, IGF-I is internalized and transported to distinct intracellular compartments that depend on the cell location within the monolayer. In resting cells away from the periphery of the monolayer, IGF-I is internalized by a clathrin coated pit pathway and delivered to the endosomal compartment. In contrast, cells(More)
Information regarding the impact of chronic renal failure (CRF) on IGF-1 serum clearance is limited. Thus we evaluated the pharmacokinetics of insulin-like growth factor-1 (IGF-1) in six normal adults and six adults with advanced CRF (serum creatinine 7 +/- 0.8 mg/dl). All subjects were given 80 micrograms/kg recombinant human IGF-1 s.c. and blood was(More)
Linear growth retardation in children with chronic kidney disease (CKD) has been ascribed to insensitivity to growth hormone. This resistance state has been attributed to impaired growth hormone signaling through the JAK2/STAT5 pathway in liver and skeletal muscle leading to reduced insulin-like growth factor-I (IGF-I). Here we determine whether systemic(More)
BACKGROUND Treatment with recombinant human growth hormone (GH) is the standard therapy for short stature in children with chronic kidney disease (CKD). However, concerns have been raised on the potential renal fibrogenic effects of GH. There is no information regarding the renal GH receptor (GHR)-JAK-STAT signaling pathway in CKD. METHODS Subtotal(More)
Resistance to growth hormone (GH)-induced insulin-like growth factor-1 (IGF-1) gene expression contributes to uremic muscle wasting. Since exercise stimulates muscle IGF-1 expression independent of GH, we tested whether work overload (WO) could increase skeletal muscle IGF-1 expression in uremia and thus bypass the defective GH action. Furthermore, to(More)