Faculty Bibliography

To determine whether saline loading actually protects against acute renal failure, both C and BUN were measured in rats drinking either tap water or 1% saline for 1-3 months. At 24 and 48 h after an injection of 10 ml/kg i.m. of 50% glycerol in water, CTN was equally reduced in saline-drinking and water-drinking rats as compared to uninjected rats. The daily intraperitoneal injection of saline for 1-3 months also was not protective. At 48 hours after glycerol injection, the BUN concentration in saline-drinking rats was significantly lower than in water-drinking rats. This was probably due to the greater renal urea clearance in these animals. We conclude from these findings that saline loading does not protect against glycerol-induced acute renal failure in the rat although it affects the Curea and Bun concentration.

13 cases of Goldenhar-Gorlin syndrome are presented in which numerous central nervous system anomalies have been found. These others. Pertinent literature has been reviewed. It is concluded that any part of the central nervous system can be involved in this condition and that careful evaluation is indicated in order to rule

The effect of lithium ingestion on intestinal electrolyte and water transport was studied in adult Sprague-Dawley rats. We fed animals a lithium-supplemented diet for 1, 2, 4, or 16 wk before in vivo perfusion of the jejunum and colon. Lithium feeding did not alter jejunal transport of water, electrolytes, or glucose, However, at 4 and 16 wk (16-wk data given) the colon increased net water (168%), sodium (160%), and chloride (140%) absorptions, and the transmural potential difference (396%) as compared with control animals. In addition, the colon absorbed both bicarbonate and potassium against an unfavorable electrochemical gradient. The increased colonic sodium absorption was not associated with an increase in mucosal Na+, K+-ATPase activity. Furthermore, in lithium-fed animals deoxycorticosterone acetate stimulated mucosal Na+, K+-ATPase activity, but it did not further increase net sodium absorption. Neither jejunal nor colonic electrolyte transport was affected 24 h after being gavage-fed lithium. These results suggest that chronic lithium ingestion has a unique mechanism of action as other means of chronically increasing sodium absorption are associated with increased mucosal Na+, K+-ATPase activity

Mineralocorticoid and glucocorticoid effects on colonic electrolyte absorption were compared by examining the alterations caused by spironolactone and amiloride in corticosteroid-treated rats. Animals were treated for 3 days with deoxycorticosterone acetate (DOCA; 0.5 mg . 100 g-1 . day-1), methylprednisolone (MP; 3 or 0.5 mg . 100 g-1 . day), and spironolactone (14 mg . 100 g-1 . day-1 im) singly or in combination. On day 4, rats were anesthetized with pentobarbital sodium and perfused in vivo with Ringer-HCO3 solution. Both doses of MP and DOCA increased net colonic sodium and water absorption and mucosal Na-K-ATPase activity. Concurrent spironolactone treatment completely prevented these effects in DOCA-treated rats but had no effect in MP-treated rats. Untreated, MP-treated, and DOCA-treated animals were perfused with a Ringer-HCO3 solution containing 1 mM amiloride. Amiloride reduced net colonic sodium and water absorption, transmural potential difference, and potassium secretion in all rats by approximately 55%. These effects were almost immediate and completely reversible. These findings in the rat suggest that 1) different receptors mediate the colonic effects of mineralocorticoids and glucocorticoids and 2) these corticosteroids do not differ in their relative effects on amiloride-sensitive and amiloride-resistant colonic sodium transport processes

Administration of the glucocorticoid methylprednisolone (MP) (30 mg/kg body wt for 3 days) to rats increased intestinal mucosal guanylate cyclase and Na-K-ATPase activities, short-circuit current (Isc), electrical potential difference (PD), net Na absorption, and net Cl secretion and reversed HCO3 transport from secretion to absorption. In the MP-treated animals, removal of HCO3 from both the mucosal and serosal bathing solutions increased Cl secretion but did not alter the Isc, PD, and net Na flux. Removal of Cl abolished the MP-induced increase in Isc but did not affect the MP-induced changes in net Na and HCO3 fluxes. At 6 h, after a single dose of MP, stimulation of guanylate cyclase activity was already maximal, whereas Na-K-ATPase activity was not detectably altered. The changes in intestinal transport properties present 6 h after MP treatment and associated with the increased guanylate cyclase activity were an increase in Isc and PD and a reversal of net Cl absorption to net secretion. These results suggest that an initial response to MP administration is a persistent increase in intestinal guanylate cyclase activity that mediates an electrogenic Cl secretory process, then is followed by a superimposed effect of increased Na-K-ATPase activity that mediates an increase in net Na absorption

Renal and cardiac effects of norepinephrine and dopamine were evaluated in swine aged 1 wk, 2 wk, and 6 mo. The swine were anesthetized with pentobarbital (20-30 mg/kg). Aortic pressure, right ventricular pressure and its first derivative, and heart rate were recorded, together with carotid and renal (RBF) arterial flows. Glomerular filtration rate (GFR) was determined by [14C]inulin clearance. After a control period, norepinephrine or dopamine was infused intravenously for 10-20 min before and then during another clearance period. After a second control period, the second catecholamine was infused. GFR increased in piglets given either catecholamine. Norepinephrine at equipressor doses (2.0 micrograms.kg-1.min-1 in piglets and 1.0 micrograms.kg-1.min-1 in mature swine) decreased RBF and increased renal resistance. Dopamine at equi-inotropic doses (10 micrograms.kg-1 min-1 in piglets and 20 micrograms.kg-1.min-1 in mature swine) increased RBF and decreased renal resistance only in mature swine. Infusions of dopamine at a low dose (5 micrograms.kg-1.min-1) also failed to increase RBF or decrease renal resistance in piglets. The results suggest that maturation of the mechanism of renal vasodilation by dopamine occurs later than that for vasoconstriction by norepinephrine