No abstract

Significant variability in emergency presentation of CRC requires local audit and examination of the reasons for delay in diagnosis and targeted measures to improve performance in non-emergency referral pathways.

Negligible antidiuretic activity (less than 0.17 mU./g.) was found in extracts of the kidneys either of unanaesthetized adult rats in normal water balance or of rats in whose blood a rise of the level of endogenous antidiuretic hormone had been induced by ether anaesthesia. Extracts of the livers of unanaesthetized rats had negligible antidiuretic activity (less than 0.06 mU./g.),but liver extracts from rats anaesthetized with ether showed antidiuretic effects equivalent to 0.74 ±0.24 mU. Pitressin/g. liver. When Pitressin was injected intravenously into unanaesthetized rats, small amounts of antidiuretic activity were occasionally found in the livers and the kidneys of animals killed up to 3 mmn. after the injection but none in animals killed later. Some 3% of the antidiuretic activity of an injected dose of Pitressin was found in the urine and the " dead space" of the kidneys in rats decapitated 3 min. after the intravenous injection. When Pitressin was added to rat kidney homogenate and the mixture was incubated at 380, only 0.75% of the initial antidiuretic activity was recovered after 30 min. and less than 0.40% after 60 min. Experiments with " glomerular " and " tubular " fractions of rat kidney indicated that the inactivation was essentially due to tubular tissue. It is suggested that, in the rat, the kidneys and perhaps the liver are not only sites of clearance of the antidiuretic hormone but also sites of irreversible inactivation. Ginsburg and Heller (1953a) and Crawford and Pinkham (1954) showed that, after intravenous injection into intact rats, the antidiuretic activity of doses of Pitressin (Parke Davis) ranging from 5 to 100 mU. /100 g. body weight disappeared rapidly from the circulation: 5 min. after the injection less than 5% of the injected antidiuretic activity could be recovered from the blood. Similar experiments were done by Dicker (1954), who infused rats with pitressin at rates ranging from 30 to 100 1MU. /min. / 100 g. In 4 of his animals, killed 2 to 3 min. after the end of the infusion, no antidiuretic activity could be demonstrated in the plasma; in two others the recovery was equivalent to about 1 % of the infused dose. However, when pitressin was injected or infused into nephrectomized rats (Ginsburg and Heller, 1953a;Crawford and Pinkham, 1954;Dicker, 1954), it was found that the antidiuretic activity was " cleared " at a considerably lower rate, the recovery after 2 to 5 min. varying from 37 to 63 % of the administered dose. Sham-nephrectomized rats (Crawford and Pinkham, 1954) or animals with both ureters tied (Dicker, 1954) cleared the antidiuretic hormone at about the same rate as intact rats. It seems therefore that the kidney of the rat plays an important role in the removal of antidiuretic hormone from the circulation. But it is not the only organ so concerned. Ginsburg and Heller (1953a) found also that considerable amounts of the antidiuretic principle were removed in the splanchnic vascular bed, and Ginsburg (1957) subsequently found that little or no pressor activity wa...