We postulated that glycogen is a significant energy substrate compared with fatty acids and glucose in response to adrenergic stimulation of working rat hearts. Oxidation rates were determined at 1-min intervals by release of3H2O from [9,10-3H]oleate (0.4 mM, 1% albumin) and14CO2from exogenous [U-14C]glucose (5 mM) or, by a pulse-chase method, from [14C]glycogen. We estimated the 14C enrichment of glycogen metabolized at each time point to determine true rates of glycogen use. Based on the pattern of glycogen enrichment over time, glycogenolysis did not exhibit a high degree of preference for newly synthesized glycogen. Epinephrine (1 μM) increased contractile performance 86% but did not stimulate oleate oxidation. The increased energy demand was supplied by carbohydrates, initially by a burst of glycogenolysis (contributing 35% to total ATP synthesis for 5 min) and followed by delayed increase in the use of exogenous glucose (eventually contributing 29% to ATP synthesis). On the basis of the release of14CO2and [14C]lactate specifically from glucose or glycogen, we found that a larger portion of glycogen was oxidized compared with exogenous glucose, augmenting the yield of ATP from glycogen. Thus the heart responds to an acute increase in energy demand by selective oxidation of glycogen.

We tested the hypothesis that glycogen is preferentially oxidized in isolated working rat heart. This was accomplished by measuring the proportion of glycolytic flux (oxidation plus lactate production) specifically from glycogen which is metabolized to lactate, and comparing it to the same proportion determined concurrently from exogenous glucose during stimulation with epinephrine. After prelabeling of glycogen with either 14 C or 3 H, a dual isotope technique was used to simultaneously trace the disposition of glycogen and exogenous glucose between oxidative and non-oxidative pathways. Immediately after the addition of epinephrine (1 M), 40-50% of flux from glucose was directed towards lactate. Glycogen, however, did not contribute to lactate, being almost entirely oxidized. Further, glycogen utilization responded promptly to the abrupt increase in contractile performance with epinephrine, during the lag in stimulation of utilization of exogenous glucose, suggesting that glycogen serves as substrate reservoir to buffer rapid increases in demand. Preferential oxidation of glycogen may serve to ensure efficient generation of ATP from a limited supply of endogenous substrate, or as a mechanism to limit lactate accumulation during rapid glycogenolysis. ( J. Clin. Invest .

The late pregnancy (3rd trimester) and the postpartum period (PPP) (calving date or day zero to day 45) are very critical periods for the fertility and production in dairy cows. This study was designed to investigate blood glucose, total protein (TP), calcium (Ca), phosphorus (P), magnesium (Mg), iron (Fe), and triiodothyronine (T3) during late pregnancy and the PPP. Twenty-seven apparently healthy multiparous crossbred dairy cows (Friesian × Kenana) were included in this study. The cows were randomly allocated into three groups: group A (n = 10), cows with late pregnancy, group B (n = 7), cows in the PPP, and group C (n = 10), nonpregnant cows as control. One-way ANOVA was used to analyze the data. The results of this study showed that blood glucose was higher in late pregnancy and the PPP than in nonpregnant cows. The TP was significantly lower in late pregnant cows than during the PPP and in nonpregnant cows. Ca, P, and Mg were not significantly different between periods. Serum Fe and T3 were significantly lower during the PPP than that in late pregnant and nonpregnant cows. The results can provide indications of the nutritional status of dairy cows and a diagnostic tool to avoid the metabolic disorders that may occur during late pregnancy and the PPP.

Acute limb ischemia (ALI) is a medical emergency which can lead to loss of limb and even death. The outcomes are depending on the immediacy and completeness of revascularization or reperfusion. Generally, the considered a golden period in the management ALI is 6 hours. Unfortunately, the handling of patients with ALI is often too late. Currently there are several methods of revascularization such as thrombolysis (catheter directed thrombolysis), percutaneous and open surgical mechanical thrombectomy. The selection method where is the best revascularization remains controversial. Some research suggest that outcomes did not differ between thrombolysis and surgical therapy.