[Possible mechanisms of the renal action of dopamine in man].
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Diabetes Insipidus↗
Biomedical subjects
M Cacciari
Publications and source records attributed to M Cacciari.
Anaplastic thyroid carcinoma in a 49 year-old woman with a long-standing goiter. A case report.
A 49 year-old woman with anaplastic thyroid carcinoma came, for the first time, to our clinic with an enlarged supraclavicular lymph node. Ten years earlier she received a diagnosis of benign nodular goiter and has been followed up with ultrasonography, which never demonstrated any enlargement of her thyroid nodule and with fine needle aspiration biopsies (FNAB), that always proved normal. An ultrasonographic control, performed 10 months before diagnosis, showed the onset of a shell calcification all around the thyroid nodule that forbade the performance of FNAB. At initial examination in our endocrinology centre she was found to have an enlarged thyroid nodule (changing from 3.5 cm to 4.5 cm) and a supraclavicular lymph node 3 cm wide. The patient was therefore sent to the surgeon who performed a total thyroidectomy and a lymph node exenteration. The histological examination reported a thyroid anaplastic carcinoma, composed of osteoclast-like cells and large calcifications, which showed signs of local invasion and vessel infiltration; the supraclavicular lymph node proved to be a large metastasis of anaplastic thyroid cancer. Total body CT scan, bone scintigraphy and brain CT scan showed, respectively, lung, bone and brain metastasis. Postoperative chemotherapy was rapidly interrupted for acute toxicity. The patient died for lung, bone and brain metastasis, 2 months after initial examination.
Carcinoma↗
[Renal effects of the acute inhibition of angiotensin-converting enzyme. I. 1) Studies during normal sodium and potassium balance].
We have investigated the effective role of angiotensin II on the renal function and urinary excretion of some prostanoids in healthy women submitted to different conditions of potassium balance. To this aim we have evaluated the effects of an acute inhibition of angiotensin converting enzyme by enalapril (E). The renal function was explored by clearance (cl.) method during induced hypotonic polyuria (oral water load followed by 5% dextrose solution infusion). During 60 min cl. period the urinary PGE2, 6-keto-PGF1 alpha and TxB2 were determined by RIA method. Each subject received paired studies, in absence and presence of E (10 mg administered per os 1 hour before the water load). Basal values of plasma renin activity (PRA) and urinary aldosterone (excreted during the 24 hours before the water load) were also determined by RIA method. This study protocol was applied in normal potassium balance (n = 6) and induced moderate potassium depletion (n = 6). This paper concerns the group in normal potassium balance in both absence (N3) and presence of E (N3.E). All subjects were submitted to normal dietary intake of sodium (150 mmol/d) and potassium (50 mmol/d). The basal values of PRA, urinary aldosterone and plasma electrolytes were in the normal range. The only significant effect produced by E was a reduction in mean arterial pressure, without significant changes in creatinine cl., urinary hydro-electrolyte excretions as well as urinary excretions of prostanoids.(ABSTRACT TRUNCATED AT 250 WORDS)
Aldosterone↗
[Renal effects of the acute inhibition of angiotensin-converting enzyme. I. 2) Studies during moderate potassium depletion].
We have investigated the relative roles of angiotensin II on the renal function and urinary excretion of some prostanoids in healthy women submitted to different conditions of potassium balance. To this aim we have evaluated the effects of an acute inhibition of angiotensin converting enzyme by enalapril (E). The renal function was explored by clearance (cl.) method during induced hypotonic polyuria (oral water load followed by 5% dextrose solution infusion). During 60 min cl. period the urinary PGE2, 6-keto-PGF1 alpha and TxB2 were determined by RIA method. Each subject received paired studies, in absence and presence of E (10 mg administered per os 1 hour before the water load). Basal values of plasma renin activity (PRA) and urinary aldosterone (excreted during the 24 hours before the water load) were also determined by RIA method. This study protocol was applied in normal potassium balance (n = 6) and induced moderate potassium depletion (n = 6). This paper concerns the group in potassium depletion in both absence (D4) and presence of E (D4.E). Potassium depletion was induced by adaptation to a normal sodium (150 mmol/d) and low potassium (< or = 10 mmol/d) dietary intake combined to natriuretic treatment. The water and NaCl net losses were restored by 0.9% NaCl solution infusion. The cumulative potassium deficit achieved at the end of the depletive treatment was 214 +/- 54 mmol. This treatment induced significant decrease in basal plasma potassium concentration and increase in PRA without affecting urinary aldosterone and plasma sodium concentration.(ABSTRACT TRUNCATED AT 250 WORDS)
Aldosterone↗
[Renal effects of the acute inhibition of angiotensin-converting enzyme. I. 3) Relative roles of angiotensin II and prostanoids in early hypokalemic dysfunction].
We have investigated the relative roles of some renal prostanoids and angiotensin II in the hypokalemic renal dysfunction. To this aim we have evaluated the renal function in healthy women in induced potassium depletion of moderate degree before and after acute inhibition of cyclooxygenase (indomethacin, I) or angiotensin converting enzyme (enalapril, E). The renal function was explored by clearance (cl.) method during hypotonic polyuria induced by oral water load followed by 5% dextrose solution infusion; the urinary PGE2, 6-keto-PGF1 alpha and TxB2 were determined by RIA method. Potassium depletion was induced in 12 subjects by adaptation to low potassium (< or = 10 mmol/d) and normal sodium (150 mmol/d) dietary intake combined to natriuretic treatment. The water and NaCl net losses were restored by 0.9% NaCl solution infusion. In 6 subjects paired functional studies were performed in absence (D3) and presence of I (D3.I), 100 mg administered i.m. immediately before the water load. In other 6 subjects, paired studies were performed in absence (D4) and presence of E (D4.E), 10 mg administered per os 1 hour before the water load. No significant difference between D3 and D4 was observed as regards the potassium cumulative deficit as well as the basal values of plasma potassium concentration and plasma renin activity.(ABSTRACT TRUNCATED AT 250 WORDS)
Angiotensin II↗
[Dopamine, catecholamine receptors, and neurohumoral regulation of renal function].
Were studied in healthy human subjects under conditions of hydro-saline retention the intrarenal mechanism underlying the hydronatriuretic effect of Dopamine (DA) and the changes in DA renal effects induced by Sulpiride (S). DA was infused i.v. in a subpressor dose (0,1 microgram/kg . min) during induced hypotonic polyuria. In each experiment four clearance periods of 15 min were performed; DA was administered during the second and third clearance periods. The glomerular filtration rate and renal effective plasma flow were estimated as endogenous creatinine and PAH clearances, respectively. Tubular sodium and potassium reabsorptions were also determined. 1) In the state of hydro-saline retention, renal arteriolar (mainly preglomerular) vasodilation was produced by DA. Moreover, both sodium isosmotic reabsorption as a percentage of sodium filtered load and sodium anisosmotic reabsorption as a percentage of sodium distal load were inhibited. These tubular inhibitions were found to be correlated with the haemodynamic effects of DA. 2) Sulpiride treatment (4,4 mg/kg . day given orally for two days prior to the experiment and 100 mg i.m. 40 min before DA infusion) caused (a) an increase in the hydro-natriuretic response to hydration during control clearance and (b) a decrease in DA haemodynamic effects. An interpretation is proposed accounting for these DA effects as well as for dependence of DA renal effects on the extracellular fluid volume.
Adult↗
[Extrinsic catecholaminergic control of the renal function during water and salt depletion].
Renal function was studied by means of the clearance method in the healthy subject during hypotonic polyuria induced in initial depletion conditions with or without adrenolytic treatment. Three experiments were performed: a) 19 in water-salt depletion; b) 9 in depletion associated with (+/-)-propranolol; c) 9 in depletion associated with prazosin. 15' clearance periods were carried out during control, dopamine infusion in a subpressor dose (0.1 microgram x kg-1 x min-1) and after suspension, respectively. PAH and endogenous creatinine clearance was also determined, Propranolol made no significant difference to renal function by comparison with simple depletion, whereas the more intense depletive effect of prazosin lead to a significant reduction in renal plasma flow and the glomerular filtration rate. Isosmotic and anisosmotic reabsorption of sodium (in % of the respective loads) was inhibited despite reduction of the filtrate and of the distal sodium load. Dopamine was ineffective as a vasodilator and natriuretic in water and salt depletion, while it displayed significant sodium-retaining properties. Pretreatment with propranolol and prazosin allowed dopamine to show vasodilator and hydrosaluretic effects during depletion. These results are in line with the view that the renal vasal and tubular alpha-adrenergic receptors make a significant contribution to the water and salt conservation associated with volume depletion, and that dopamine influences renal function under these experimental conditions probably by activating prejunctional beta-adrenergic receptors of noradrenergic nerve endings.
Adult↗
[Dopamine as a regulator of natriuresis. Experimental bases and their implications].
Renal effects of dopamine (DA) infused i.v. in a subpressor dose (0.1 microgram. kg.-1 min-1) were investigated in healthy human subjects during steady hypotonic polyuria. In each experiment four clearance (cl.) periods of 15 min were performed; DA was administered during the second and the third cl. periods. The glomerular filtration rate and renal effective plasma flow were estimated as endogenous creatinine and PAH clearances. Moreover the following variables were evaluated: a) sodium total and sodium isosmotic reabsorption as a % of sodium filtered load (s.f.l.); b) sodium anisosmotic reabsorption as a % of sodium distal load (s.d.l.); c) total renal vascular resistance (RT), arteriolar afferent (RA) and efferent (RE) resistances. Three groups of experiments were performed: A) in hydro-saline retention by DOCA pretreatment (24 subjects); B) in hydro-saline depletion by natriuretic pretreatment (20 subjects); C) in hydro-saline depletion and beta-adrenergic blockade induced by natriuretic and propranolol pretreatments (9 subjects). In A experimental condition DA significantly increased renal plasma flow, glomerular filtration rate, urinary flow, urine sodium concentration and osmolarity; on the contrary DA significantly decreased RT, RA, sodium total and isosmotic reabsorption, % of s.f.l., and sodium anisosmotic reabsorption, % of s.d.l. In B condition no significant changes were observed during DA infusion in either haemodynamic parameters or urinary flow; on the other hand DA significantly blunted urinary osmolarity, urinary sodium concentration and sodium excretion rate suggesting an increased sodium anisosmotic reabsorption (% of s.d.l.). In C condition the vasodilating and hydrosaluretic effects of DA were restored. Our results suggest that DA activates, besides "dopaminic" vascular receptors, the presynaptic facilitory beta-adrenergic receptors in renal adrenergic pathways. Thus the renal action of DA depends on renal adrenergic activity.
Adult↗
Studies on renal function in healthy women with different degrees of induced potassium depletion. 1) Hormonal changes relevant to salt and water balance.
In healthy women we have studied the effects of potassium depletions of different degrees on the generation of some bioregulators of hydro-saline balance. The study has been performed on 20 women in normal potassium balance (N group) and 20 women submitted to potassium depletive treatment by dietary and pharmacological means. On the basis of different patterns of treatment we have obtained three groups i.e. KD1 (n = 8), KD2 (n = 6) and KD3 (n = 6) with potassium cumulative deficit of 160 +/- 43, 198 +/- 22 and 214 +/- 54 mmol, respectively. The renal function was assessed by the clearance method during induced hypotonic polyuria and subsequent moderate antidiuresis induced by low dose infusion of lysine-8-vasopressin. The urinary PGE2, 6-keto-PGF1 (6KPGF) and TxB2 were determined by the RIA method. Moreover, the basal PRA and urinary aldosterone were determined before the renal functional exploration. The data obtained in both KD2 and KD3 groups where renal hypokalemic dysfunctions occurred--indicate that hypokalemia stimulated renin secretion and inhibited the reactivity of renal prostanoid production to the polyuric stimulus. However, in the KD3 group--where the circulating levels of renin, and probably of angiotensin II were the highest--the hypokalemic depression of the synthesis of 6KPGF and TxB2 precursors was attenuated while the synthesis of PGE2 was still inhibited.
Adult↗
Responses of the renal prostanoids to a short-term depletion of sodium or potassium in healthy women.
The short-term effects of extracellular fluid volume depletion on the generation of some bioregulators of the renal function have been studied in healthy women. Eight subjects (SD group) were submitted to a low NaCl dietary intake and natriuretic treatment. At the end of the treatment (6 days) a cumulative sodium deficit of 381 +/- 55 mmol (mean +/- SEM) and a body weight variation of -2.1 +/- 0.28 kg were estimated. The renal function was explored by clearance method during hypotonic polyuria induced by oral water load and subsequent antidiuresis induced by low-dose infusion of lysine-8-vasopressin. The basal values of plasma renin activity were determined just before the water load as well as the urinary aldosterone excretion of the foregoing 24 hours was. During the renal functional exploration the urinary concentrations of PGE2, 6-keto-PGF1 alpha (6KPGF) and TxB2 were determined by RIA method. We report also, as comparison terms, the results obtained either in potassium depletion (KD group, n = 12) or in normal sodium and potassium balance (N group, n = 20). 1) In the SD vs N group-besides the increase in renin and aldosterone secretion-the behaviour of urinary prostanoids is consistent with a stimulation of the renal synthesis of PGI2 and TxA2 as well as of PGE2, at least as a trend. 2) In the KD vs N group an increase in renin secretion occurred while the urinary aldosterone was not significantly decreased. The urinary prostanoid data suggest an inhibition of the renal synthesis of PGE2 and PGI2. All three urinary prostanoids were significantly lower in the KD as compared to the SD group. Thus, in salt depletion the renal prostanoid synthesis was enhanced while it was depressed in potassium depletion, despite the increased renin secretion.
Adult↗
Interactions between acute effect of angiotensin converting enzyme inhibition and salt balance on the renal function and urinary prostanoids. Studies in healthy women.
The acute effects of angiotensin converting enzyme inhibition on the renal function and urinary prostanoids were studied. Healthy women were studied in both sodium depletion (n = 8) and normal balance of sodium and potassium (n = 6). Each woman underwent paired renal functional explorations (by the clearance method during hypotonic polyuria and subsequent antidiuresis) in the absence and in the presence of enalapril. In both experimental conditions enalapril failed to affect urinary prostanoid excretions. Only in the presence of hyperreninemia induced by salt depletion, enalapril was effective in inducing renal tubular effects only partly consistent with a depressed activity of angiotensin-aldosterone system. Specifically, in sodium depletion enalapril treatment promoted a decreasing trend in urinary salt excretion, dependent in turn on selective stimulation of the distal tubule NaCl transport. Furthermore, plasma potassium concentration was reduced despite the concomitant decrease in urinary potassium excretion.
Adult↗