The effect of insulin on the incorporation of radioactive leucine into growth hormone was investigated by using rat anterior pituitary glands incubated in vitro. A 50% stimulation over control values was observed at insulin concentrations above 2mum (280munits/ml). The effect was specific for growth hormone biosynthesis, over the range 1-5mum-insulin (140-700munits/ml). Lower more physiological...

In the presence of transition metal ions and peroxides, polyphenols, well-known dietary antioxidants, can act as pro-oxidants. We investigated the effect of 13 polyphenols and their metabolites on oxidative degradation of deoxyribose by an •OH generating Fenton system (Fe2+-ethylenediaminetetraacetic acid (EDTA)-H₂O₂). The relationship between phenolics pro-oxidant/anti-oxidant effects and thei...

Diabetes pathology derives from the combination of hyperglycemia and hypoinsulinemia or insulin resistance leading to diabetic complications including diabetic neuropathy, nephropathy and retinopathy. Diabetic retinopathy is characterized by numerous retinal defects affecting the vasculature and the neuro-retina, but the relative contributions of the loss of retinal insulin signaling and hyperg...

The ascending thin limbs (ATLs) and lower descending thin limbs (DTLs) of Henle's loop in the inner medulla of the rat are highly permeable to urea, and yet no urea transporters have been identified in these sections. We hypothesized that novel, yet-unidentified transporters in these tubule segments could explain the high urea permeability. cDNAs encoding for Na(+)-glucose transporter 1a (SGLT1...

Methods have been developed for producing functional, transporting monolayers of avian proximal tubule (PT) cells. A highly homogenous fraction of PT fragments was prepared by enzymatic digestion (collagenase + Dispase) of chick (3- to 5-day-old) kidneys, followed by Percoll gradient centrifugation. The PT fraction was enriched in glucose-6-phosphatase, a proximal enzyme marker, and reduced in ...

Calcium is excreted by the kidneys after tubular reabsorption of its diffusible (non-protein-bound) component. There is no evidence to date to suggest that tubular secretion of calcium occurs in the mammalian nephron. In fact, recent studies utilizing the stop-flow technique indicate that calcium is reabsorbed in both the proximal and distal portion of the nephron.' The stop-flow studies1 toget...

Neurotensin (NT) is a neurohormone produced in the central nervous system and in the gut epithelium by the enteroendocrine N cell. NT may play a role in appetite regulation and may have potential in obesity treatment. Glucose ingestion stimulates NT secretion in healthy young humans, but the mechanisms involved are not well understood. Here, we show that rats express NT in the gut and that gluc...

LEE, J, S. Contraction of villi and fluid transport in dog jejunal mucosa in vitro. Am. J. Physiol. 221(2) : 488-495. 1971.-An intestinal mucosal membrane preparation permitting simultaneous determination of the fluid transport rate and a microscopic examination of villi was employed. The occurrence of sustained villus shortening was invariably associated with diminution or abolition of fluid t...

Adenosine modulates the intestinal functions of secretion, motility, and immunity, yet little is known about the regulation of nutrient absorption. Therefore, we measured the carrier-mediated uptake of tracer D-[(14)C]glucose (2 microM) by everted sleeves of the mouse intestine after a lumenal exposure to adenosine and a disodium salt of AMP. Rates of glucose uptake by intact tissues increased ...

In the present study we investigated a possible involvement of the intestinal sodium-dependent glucose transporter (SGLT)1 in the absorption of quercetin-3-glucoside (Q3G). Pieces of rat jejunum or proximal colon were mounted in Ussing-type chambers and incubated under short-circuited conditions. Test flavonols were added to the mucosal or serosal bathing solution (initial concentration, 100 mi...