SYNOPSIS The case histories of 4 children with Bartter's syndrome are presented. All were born prematurely and pregnancy was associated with hydramnios. All failed to thrive and had a vasopressin‐insensitive urinary concentrating defect, but were of normal intelligence. Hypo‐kalaemia was not necessarily present when first seen, but serum sodium was low compared with other patients with diabetes insipidus. Salt loading caused a sharp fall in serum potassium, often associated with a paradoxical rise in plasma renin levels. Urine calcium was high in all patients and rose to very high levels with salt loading. Nephrocalcinosis was a constant finding. The basic defect is thought to be one of ion absorption in the proximal tubule, though membrane transport may also be affected in other areas.

Synthetic N-terminal 34 amino acid peptide of bovine parathyroid hormone (PTH) produced a consistent rise in plasma renin activity in saline-loaded dogs when given iv either as a single bolus dose of 400 U or infused steadily in lower dosage over a number of hours. Infusion of as little as 1 U/min produced a significant rise in plasma renin activity, but a greater effect was obtained with 2 U/min. Infusion of 4 U/min had no more effect than 2 U/min. In contrast to transient hypotension after rapid injection of a single large dose, blood pressure did not change significantly during the steady infusion of lower doses of PTH. These findings are compatible with the thesis that an increased distal tubular load of sodium stimulates renin release and suggest that the increased distal sodium absorption after the proximal effects of PTH may be regulated by the renin-angiotensin-aldosterone system.

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Patients with NS have several disorders of calcium metabolism: hypocalcemia, hypocalciuria and probably decreased intestinal absorption of calcium. In order to evaluate the mechanisms responsible we have studied in 23 children, 3-12 years old, with NS and normal rend1 function, total and ionized calcium, calciuria, and blood levels of 25-hydroxyvitamin D and of Cc-protein.The studies were performed when proteinuria was>200 mglhlmq and repeated during remission of NS. The blood levels of 25HCC and of Gc-protein were significantly lower than that in normdl subjects (p<0.01) and there wds d direct correlation between albuminemia and pldsma levels of 25HCC, and an inverse correlation between the degree of proteinuria and 25 HCC. The loss of metabolites of vitamin D circulating bound to Gcproteins seems the main cause of the disorders in calcium metabolism observed in NS. parameter can be estimated from the data of intake, NAE can be predicted. In steady state conditions the urinary excretion of electrolytes correlates with their intestinal absorption, which can be estimated from intake and absorption rate. Absorption from the gut was estimated in the following way: Na + Cl: 100%; K: 90%; Ca: 0.17 x Ca intake (mg) + 60; Mg: 0.39 x Mg intdke (mg) -23; P: 0.642 x P intake (mg) -11. 75% of the ingested organic sulfur (methionine and cystine) is oxidized to SO dnd excreted in the urine. 03 excretion is almost independent ?rum the diet (38 meq/d/1.73m ). The usefulness of this theoretical model to estimate NAE was demonstrated in acid-base studies of children with phenylketonuria receiving two synthetic amino acid mixtures (PAM with a high NAE of 4-6 meq/kg/d, PAM74with a low NAE of 1 meq/kg/d).FAMILIAL HYPOKALAEMIA AND HYPOMAGNESAEMIA. GITELMAN'S SYNDROME. REPORT OF 6 CASES. McCredie, D.A., Powell, 3 H.R., and Rotenberg, E., Dept. of Paediatrics, University of Melbourne, Austrdlid.Six cases of renal wdsting of potassium and mdgnesium are described in four families. Four patients presented with tetany, whilst two were asymptomatic siblings of these. One patient also suffered from a progressive external ophthalmoplegia syndrome and mental retardation, whilst the remaining five were normal in physical and intellectual development. One patient (now aged 31 yrnrs) hns subsequently giver^ birth t o two r~urrn.al clllldrt,rx, but maintains very low serum levels of both potassium (2.0 mM) and magnesium (0.5 mM) when off electrolyte therapy. No abnormalities in calcium metabolism were found and there was no other evidence of tubular reabsorptive defect apart from slight defects in urinary concentration and acidification. In particular sodium chloride conservation appeared normal. Plasma renin levels were normal, or slightly raised in these patients and urinary aldosterone levels were normal, distinguishing this condition from Bartter's syndrome. Magnesium loading did not affect potassium wasting, nor did potassium loading alter the renal handling of magnesium. Spironolactone was able to improve tubular reabsorption of potassium, ...

1. A rapid increase in plasma renin activity occurred in dogs after intravenous administration of parathyroid extract. 2. This was not seen after injection of a purer parathormone preparation, or the solution used to dilute the parathyroid extract or calcitonin. 3. A vasoactive compound in parathyroid extract appears to provide the most likely explantation of this effect.