Effect of circulation time on plasma high density lipoprotein cholesterol in rats

Abstract

The effect of circulation time on plasma high density lipoprotein cholesterol concentrations was investigated in 20 male Wistar rats injected with alcohol, stressed with lighting, or fed a high fat diet. Circulation time was measured during anaesthesia with a computerised dichromatic earpiece densitometer. Indocyanine green, 0.5% concentration and 0.05 ml volume, was injected directly into the intracardiac cavity. The densitometer was held against the right foot of the rat, where the concentration of indocyanine green was measured by a light absorption method. Circulation time was defined as the time during which indocyanine green passed from the heart to the foot. At the same time blood was collected for determining high density lipoprotein cholesterol concentration. The rats were randomly divided into three groups, and control circulation time and high density lipoprotein cholesterol concentrations were obtained. In six rats injected with 100% ethyl alcohol, 0.03 ml.100 g-1 body weight in volume, into the abdominal cavity and five rats placed under 400 Lux lighting for 48 h the increase in circulation time was inversely proportional to the increase in high density lipoprotein cholesterol concentration (r = -0.644, p less than 0.05). Of nine rats given a high fat diet containing 7.0% fat for 48 h, all showed increased high density lipoprotein cholesterol concentration, but no correlation was noted between the increases in circulation time and high density lipoprotein cholesterol (r = -0.303).(ABSTRACT TRUNCATED AT 250 WORDS)

Direct arterial injection of hyperpolarized 13C‐labeled substrates into rat tumors for rapid MR detection of metabolism with minimal substrate dilution

“…The significantly enhanced pyruvate signal in the tumor for IA compared with IV administration indicates rapid extraction of pyruvate from the circulation into the tumor tissue on first pass. The circulation time in rats at the body weights used in our experiments was approximately 7 s , so the recirculation of hyperpolarized pyruvate would have approximately coincided with the end of the infusion period. In addition, any pyruvate not extracted by the tumor tissue on first pass would have been largely diluted in the systemic circulation, while also rapidly losing signal.…”