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Although most attention has been focused on mitochondrial ATP production and transfer in failing hearts, less has been focused on the nonfailing hypertensive heart. Here, energetic complications are less obvious, yet they may provide insight into disease ontogeny. We studied hearts from 12-mo-old spontaneously hypertensive rats (SHR) relative to normotensive Wistar-Kyoto (WKY) rats. The ex vivo working-heart model of SHR showed reduced compliance and impaired responses to increasing preloads. High-resolution respirometry showed higher state 3 (with excess ADP) respiration in SHR left ventricle fibers with complex I substrates and maximal uncoupled respiration with complex I + complex II substrates. Respiration with ATP was depressed 15% in SHR fibers relative to WKY fibers, suggesting impaired ATP hydrolysis. This finding was consistent with a 50% depression of actomyosin ATPase activities. Superoxide production from SHR fibers was similar to that from WKY fibers respiring with ADP; however, it was increased by 15% with ATP. In addition, the apparent Km for ADP was 54% higher for SHR fibers, and assays conducted after ex vivo work showed a 28% depression of complex I in SHR, but not WKY, fibers. Transmission electron microscopy showed similar mitochondrial volumes but a decrease in the number of cristae in SHR mitochondria. Tissue lipid peroxidation was also 15% greater in SHR left ventricle. Overall, these data suggest that although cardiac mitochondria from nonfailing SHR hearts function marginally better than those from WKY hearts, they show dysfunction after intense work. Impaired ATP turnover in hard-working SHR hearts may starve cardiac mitochondria of ADP and elevate superoxide. adenylate control; saponin-permeabilized fibers; hypertensive heart; oxidative stress; complex I dysfunction; respiration

Mesenteric lymph contributes to normal homeostasis and has an emerging role in the pathogenesis of multiple organ dysfunction syndrome. The aim of this study was to define the proteome of normal rodent mesenteric lymph in the fasted and fed states. Eight male Wistar rats fed a standard rodent diet were randomized to two groups. Group 1 (fasted, n = 4) were fasted for 24 h before anesthetized collection of mesenteric lymph. Group 2 (fed, n = 4) were allowed ad libitum access to food before lymph collection. Mesenteric lymph was subjected to proteomic analysis using iTRAQ and liquid chromatography-tandem mass spectrometry (LC-MS/MS). One hundred fifty proteins, including 26 hypothetical proteins, were identified in this study. All proteins were identified in lymph from both the fasted and fed states. The relative distribution profiles of protein functional classes in the mesenteric lymph differed significantly from that reported for plasma. The most abundant classes identified in lymph were protease inhibitors (16%) and proteins related to innate immunity (12%). In conclusion, this study provides the first detailed description of the normal mesenteric lymph proteome in the fed and fasted states using iTRAQ and LC-MS/MS. rat; fed; fasted

Desacetyl [alpha]-MSH predominates over [alpha]-MSH during development, but whether it is biologically active and has a physiological role is unclear. We compared the effects of 0.3 [micro]g*[g-l]*[day.sup.-1] desacetyl [alpha]-MSH with that of 0.3 [micro]g*[g.sup.-1*[day.sup.-1] [alpha]-MSH on postnatal body growth by administering the peptides subcutaneously daily for postnatal days 0-14 and also used a two-dimensional gel electrophoresis gel-based proteomic approach to analyze protein changes in hypothalami, the relay center for body weight and growth regulation, after 14 days of treatment. We found that the growth rate between days 1 and 10 was significantly decreased by desacetyl [alpha]-MSH but not by [alpha]-MSH, but by day 14, a time reported for development of a mature pattern of hypothalamic innervation, both peptides had significantly increased neonatal growth compared with PBS-treated control rats. Desacetyl [alpha]-MSH significantly increased spleen weight, but [alpha]-MSH had no effect. [alpha]-MSH significantly decreased kidney weight, but desacetyl [alpha]-MSH had no effect. Both desacetyl [alpha]-MSH and [alpha]-MSH significantly decreased brain weight. By 14 days, both peptides significantly changed expression of a number of hypothalamic proteins, specifically metabolic enzymes, cytoskeleton, signaling, and stress response proteins. We show that peripherally administered desacetyl [alpha]-MSH is biologically active and induces responses that can differ from those for [alpha]-MSH. In conclusion, desacetyl [alpha]-MSH appears to be an important regulator of neonatal rat growth. melanocortin peptides; [alpha]-melanocyte-stimulating hormone; melano-cortin receptors; proopiomelanocortin; hypothalamus

Altered metabolism of the inositol sugars myo-inositol (MI) and D-chiro-inositol is implicated in diabetic complications. In animals, catabolism of MI and D-chiro-inositol depends on the enzyme MI oxygenase (MIOX), which catalyzes the first committed step of the glucuronate-xylulose pathway, and is found almost exclusively in the kidneys. The crystal structure of MIOX, in complex with MI, has been determined by multiwavelength anomalous diffraction methods and refined at 2.0-[Angstrom] resolution (R = 0.206, [R.sub.free] = 0.253). The structure reveals a monomeric, single-domain protein with a mostly helical fold that is distantly related to the diverse HD domain superfamily. Five helices form the structural core and provide six ligands (four His and two Asp) for the di-iron center, in which the two iron atoms are bridged by a putative hydroxide ion and one of the Asp ligands, Asp-124. A key loop forms a lid over the MI substrate, which is coordinated in bidentate mode to one iron atom. It is proposed that this mode of iron coordination, and interaction with a key Lys residue, activate MI for bond cleavage. The structure also reveals the basis of substrate specificity and suggests routes for the development of specific MIOX inhibitors. diabetes | substrate binding | metalloprotein | HD domain | polyol metabolism

Experiments were performed to investigate the systemic effects of amylin and its potential use in treating osteoporosis. Systemic administration of amylin resulted in histomorphometric changes in bone formation and resorption such as an elevated bone mass which was attributed to an increase in osteoblast activity. Changes in the width of the growth plate and on tibial length identify the chondrocyte as another amylin target cell. Moreover, the findings have potential value in treating and understanding osteoporosis.

Research shows that vasodilator adrenomedullin controls osteoblast activity and stimulates bone mass production in vivo. Experiments using osteoblasts from fetal rat calvaria are described. The 52-amino acid peptide chain induces bone formation by causing increased phenylalanine incorporation into osteoblast cells. The effects of adrenomedullin treatment on fetal rat osteoblast cells over a 24-hour period are illustrated.

The biological actions of adrenomedullin in conscious sheep were analyzed to characterize the regulatory activity of the vasodilator peptide on renal performance, renal hemodynamics and endocrine activity. Infusions of adrenomedullin resulted in clear-cut renal hemodynamic effects such as reduced filling pressure and arterial pressure. The blood-pressure lowering effects of adrenomedullin was also coupled with increased cardiac output and renin stimulation in conscious sheep.

A study examined if the hormone insulin or amylin causes the close connection between total body fat mass and bone mineral density. The anabolic influence of insulin on osteoblasis or its restriction of preparation of sex hormone-binding globulin could mediate the circulating insulin levels which are uniformly connected to bone density in the entire skeleton. The connection between amylin and bone density or fat weight in women who are not fat has not been proved by these findings.

Lightly anaesthetized rats and rats injected with insulin, fed after 20 hours of fasting, were experimented upon to determined the actions of intravenous glucagon and a recently discovered hyperglycemic pancreatic islet hormone, amylin. Glucagon is less effective in fasted animals in increasing plasma glucose. An increase in the plasma lactate is caused by amylin, and hyperglycemia is promoted by the glucagon.