Levels of cyclic adenosine monophosphate (AMP) in the basilar artery and in circulating blood of cats were determined after the production of spasm by topical application of blood to the vessel and following treatment with agents known to alter cyclic AMP. Isoproterenol, known to stimulate adenyl cyclase, and aminophylline, a phosphodiesterase inhibitor, were studied alone and in combination. Cyclic AMP of the basilar artery fell from a mean control value of 43 to 26 pmoles per milligram of protein following the production of vasospasm. Intravenous administration of isoproterenol alone and in combination with aminophylline produced dilatation of the basilar artery, which was associated with a marked rise in the cyclic AMP concentration in the vessel. The finding that cerebral vasospasm is associated with a fall and vasodilation with a rise in cyclic AMP concentration supports the hypothesis of an active role for cyclic nucleotides in the regulation of cerebrovascular smooth muscle tone.

Aminophylline↗

PubMedDate not supplied

Metabolism of chloronaphthalenes.

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Animals↗

PubMedDate not supplied

Metabolism and tissue distribution of mono-2-ethylhexyl phthalate in the rat.

The absorption, distribution and metabolic excretion of mono-2-ethylhexyl [7-14C]phthalate (MEHP) were studied in the rat. This compound was readily absorbed from the gastrointestinal tract. Radioactivity following intravenous administration of 14C-MEHP was rapidly distributed in all tissues, with the highest levels occurring in the liver, kidney, and urinary bladder. Excretion of radioactivity was rapid and approximately 80% of the dose was eliminated 24 hr after oral administration, 72% in the urine and 8% in feces. MEHP was extensively metabolized after oral administration, and the major urinary metabolites were identified as an alcohol, a ketone, and an acid resulting from the side-chain oxidation of MEHP. A trace of o-phthalic acid was also identified.

Animals↗

PubMedDate not supplied

The absorption, distribution and excretion of photomirex in the rat.

The absorption, distribution, and excretion of photomirex were investigated in the rat. Photomirex was absorbed slowly after oral administration, appeared in the blood at 1.5 hr, and reached the peak concentration 4 hr after dosing. Elimination from the blood was studied in rats receiving single intravenous doses; the semilog-arithmic decay curve was found to be triphasic. The highest concentrations were present in the rat, liver, and skin. Approximately 38--42% of the orally dosed photomirex was excreted in the feces in the first 3 days and 51--55% was eliminated in 28 days. Only trace amounts of photomirex were found in the urine (less than 0.09% of the total dose in 24 hr). Photomirex constituted about 95% of the total radioactivity found in the tissues and feces. No metabolite was detected in the radioactive material extracted from tissues or feces.

Animals↗