Hormonal regulation of leptin secretion from isolated adipose tissue of male rats

Leptin, the product of ob gene expression mainly by the white adipose tissue cells, is a plasma protein hormone appears to act as a key signaling factor for regulating body weight participating in regulation of energy homeostasis. The escalating interest in leptin study is due to its intimate relation to the worldwide prevalent problem of obesity which reached epidemic proportion.Now it's confirmed that one of the main mechanisms of obesity is decreased leptin action. Leptin seems to play dual role in human physiology being subjected to dual control [Caro et al, 1996] under chronic conditions of steady state energy balance, leptin is a static index of the amount of fat stored in the adipocytes, while under non steady state of energy balance situations leptin may be actively regulated by hormonal or nutritional changes

Stress mechanism - an emerging role for furosemide

The beneficial effect of furosemide in emergency treatment of acute left ventricular failure starts immediately with the intravenous administration before the occurrence of diuresis. Pulmonary-systemic redistribution of blood volume had been suggested in relieving the left ventricular strain. A central mechanism for furosemide could be suggested because; recent data point to furosemide high specificity and selectivity in antagonizing cerebral GABA neurotransmission and a state of neurohumoral imbalance was suggested in these patients. So this study was conducted to evaluate the potential role of furosemide in the physiological stress mechanism. The effect of a single intraperitoneal dose of furosemide [4mg/kg. of body weight] was tested in a model of emotional stress induced by ultrasound noise, on rat behavioral activity, serum corticosterone level together with the volume of diuresis. Ultrasound noise exposure in a frequency range of 30,000 Hz to 65,000 Hz led to a significant limitation of its activity [freezing reaction]. Serum corticosterone level and behavioral activity are increased significantly in furosemide treated non-stressed and stressed rats compared with both control or stressed group. The increase was marked in furosemide treated-stressed rats. The increase in serum corticosterone and behavioral activity by furosemide in stressed rats indicate a transformation of the stress state from [freezing reaction] to a state of a [defense reaction]. In conclusion; furosemide stimulates the central stress mechanism. This stimulation may be in favor of rapid and potent beneficial effect of furosemide inrecovery of neurohumoral imbalance in stress conditions which probably mediates the pituitary hypothalamic axis

Multual effect of glucose and calcium on their rates of intestinal absorption in anesthetized rats

In the present experiments the possible interaction between intestinal calcium and glucose absorption was tested in vivo. 54 rats [200-220 gm, each] were used and anaesthetised by thiopental Na 60 mg/kg I.P., abdomen was opened and 2 canulae were inserted at the proximal and distal ends of the small intestine. After preliminary wash with warm N. saline, different solutions containing CaCI[2] isotonic [1.1 gm%] or hypertonic [2.2 gm%], with and without N. saline + glucose 596, were administered into the intestine through the proximal canula and retained for 15 minutes and then pushed out by air. Volume and glucose or calcium content of the administered and collected perfusates were estimated. Calcium absorption was enhanced significantly [P<0.01] in the presence of glucose. Alternatively, hypertonic calcium produced significant inhibition of glucose absorption [P< 0.05]. This inhibitory effect of calcium was almost abolished by the addition of the Ca[++]channel blocker 'verapamil' in 4 mg/kg. Verapamil also decreased intestinal absorption of calcium significantly [P