Delta sleep-inducing peptide administration does not influence growth hormone and prolactin secretion in normal women

The aim of this study was to analyze the effects of delta sleep-inducing peptide (DSIP) on growth hormone (GH) and prolactin (PRL) secretion in eight healthy women with normal cycles (aged 17-36 years). GH and PRL secretion was studied in five women after DSIP (25 micrograms/kg bw IV over 30 min), arginine chlorhydrate (0.5 g/kg bw IV over 30 min) and simultaneous DSIP plus arginine chlorhydrate administration. In three other women the circadian rhythm of GH and PRL was studied during DSIP (25 micrograms/kg bw from 2130h to 2230h) and placebo IV infusion. Serum GH and PRL levels were normal under basal conditions and no effects were noted after the infusion of DSIP. The GH and PRL circadian rhythm was not modified by DSIP administration. DSIP did not influence GH and PRL responsiveness to arginine chlorhydrate. We found that at dosages which are known to modify ECG patterns, DSIP is unable to modify spontaneous or arginine chlorhydrate-induced GH and PRL secretion.

Effects of angiotensin converting enzyme inhibitors and calcium antagonists on atrial natriuretic peptide release and action and on albumin excretion rate in hypertensive insulin-dependent diabetic patients

Abnormalities in sodium homeostasis and in atrial natriuretic peptide (ANP) behavior could play a role in determining and accelerating the development of glomerular hypertension, hypertension, and microalbuminuria in insulin-dependent diabetes. The aim of the present study was to investigate in 32 hypertensive insulin-dependent diabetic patients (HD) with an altered albumin excretion rate the natriuretic response and ANP release to saline load (2 mmol/kg 90 min, and the effects angiotensin converting enzyme inhibitor therapy 2.5 to 5.0 mg cilazapril, once daily), and calcium antagonists (sustained release verapamil: 120 to 240 mg Isoptin Press, once daily, and long acting nifedipine: 20 to 40 mg Adalat AR, twice daily) on sodium homeostasis and albumin excretion rate. Eight normal subjects matched for sex, age, and weight served as controls. The 32 HD patients showed a blunted response in ANP release and sodium excretion during saline infusion in comparison with controls. The cilazapril and verapamil treatments were tested in 16 of the 32 HD patients and were both effective in ameliorating natriuretic and ANP response to saline load and in decreasing albumin excretion rate. The combined cilazapril and verapamil treatment further improved both these parameters in these patients, although blood pressure levels were comparable. The other 16 HD patients underwent sequential verapamil and nifedipine treatment. Verapamil was more effective than nifedipine in improving natriuresis and ANP release to saline load and in lowering the albumin excretion rate. The results of the present study demonstrate that sodium homeostasis and ANP release are altered in hypertensive nephropathic patients, and both cilazapril and verapamil are more effective than nifedipine in ameliorating natriuresis, ANP release, and albumin excretion rate.

[Long-term treatment of central diabetes insipidus with oral DDAVP]

Clinical use of the DDAVP (1-Deamino-8-D-Arginine Vasopressin) is now the first choice in treatment of Central Diabetes Insipidus. It is an analogue of Vasopressin with a higher antidiuretic potency, less vasopressor activity, and a longer duration of action. This drug still presents some problems of administration route. A lot of studies were published about different administration routes of DDAVP: sublingual tablets, parenteral solution, nose spray and suction de-epithelialized skin. Some authors have utilized the oral route (solution or tablets) with good results in short-term treatment. We think the formulation in tablets of DDAVP is an efficacious support of the therapy in this disease also for long-treatment. In our study 3 patients with Central Diabetes Insipidus (aged 22-56; 2 idiopathic and 1 post-surgery) previously treated with DDAVP nasal solution (10 micrograms/day; 36-156 months), have been submitted to a chronic treatment with DDAVP tablets for a period of 24-36 months. The DDAVP tables were administered at the dosage of 400-600 micrograms/day in 2-3 administrations. The patients were studied at intervals of 3-6 months, and on each occasion full blood count, glucose, azotaemia, creatinine, liver function tests, electrolytes, urine volume, density and osmolality were estimated. The long-treatment with oral DDAVP was able to keep a good control of the disease in all patients. In case 1 we had a significant reduction of urine volume (p < 0.01) and a significant increase (p < 0.01) of urine osmolality in comparison with previous treatment with nasal solution; in case 2 and 3 no significant changes were observed. No side effects were noted during this study. The drug has been well tolerated and the compliance of patients was better during oral DDAVP than nasal solution. In our opinion the oral DDAVP is an effective and safe solution for the treatment of Central Diabetes Insipidus, and give to the patients a better quality of life in comparison to the nasal solution.

Forearm ketone body metabolism in normal and in insulin-dependent diabetic patients

In insulin deficiency, there is excessive arterial delivery of free fatty acid (FFA) to muscles where they are converted to acetoacetyl-CoA and acetyl-CoA. These intermediates may be metabolized further to acetoacetate and beta-hydroxybutyrate, which can be released into the venous circulation. When ketone body (KB) tracers are infused in vivo, they are diluted across muscle tissue. This dilution may be due to 1) KB newly formed within muscle (ketogenesis); 2) exchange of tracer between labeled and unlabeled acetyl-CoA and acetoacetyl-CoA, intermediates common to the metabolism of both FFA and KB (pseudoketogenesis). Thus this study assessed whether such label exchange could be detected across the human forearm and whether an increased delivery of FFA in insulin-sufficient controls provoked dilution of labeled KB tracer comparable to that observed in insulin-deficient diabetics. Five normal and five insulin-dependent diabetic (IDDM) subjects were infused with labeled [3,4-13C2]-acetoacetate. [13C]KB enrichments were lower in forearm vein than in the artery, and dilution of labeled KB was always higher than that which could be explained by arterial-venous differences of unlabeled KB. When arterial FFA concentrations in normals were raised (Intralipid+heparin) to values comparable to those of the diabetics, no additional increase in forearm arteriovenous dilution of labeled KB was observed. Neither in the basal state nor under conditions of increased plasma FFA were we able to detect venous appearance of KB labeled in the first and in the second carbon atoms, a necessary consequence of pseudoketogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of atrial natriuretic peptide in the pathogenesis of sodium retention in IDDM with and without glomerular hyperfiltration

The pathogenetic determinants of sodium retention in IDDM are not fully understood. The aim of this study was to elucidate the action of ANP in 11 IDDM patients with high GFR (greater than or equal to 135 ml.min-1 x 1.73 m-2), referred to here as HF patients; in 10 IDDM patients with normal GFR (greater than 90 and less than 135 ml.min-1 x 1.73 m-2), referred to here as NF patients; and 12 control subjects, here called C subjects, at baseline and during saline infusion administered on the basis of either body weight (2 mmol.kg-1 x 60 min-1; Saline 1) or of ECV (12 mM.ECVL-1 x 90 min-1; Saline 2) during euglycemic insulin-glucose clamp. C subjects and both HF and NF IDDM patients received a second Saline 1 infusion accompanied by ANP infusion (0.02 microgram.kg-1.min-1) at euglycemic levels. HF and NF patients were studied again after 3 mo of treatment with (10 mg/day). Quinapril (CI 906, Malesci, Florence, Italy), an ACE inhibitor without sulfhydryl group. At baseline, both HF and NF IDDM patients had higher plasma ANP concentrations than C subjects (HF, 36 +/- 4, P less than 0.01 and NF, 34 +/- 3, P less than 0.01 vs. C, 19 +/- 3 pg/ml). Plasma ANP and natriuretic response to isotonic volume expansion was impaired both in HF (44 +/- 8 pg/ml, NS vs. base) and NF (40 +/- 7 pg/ml, NS vs. base) compared with C (41 +/- 4 pg/ml, P less than 0.01 vs. base) during Saline 1. On the contrary, plasma ANP response to Saline 2 was similar in HF and NF patients and C subjects, but IDDM patients had still lower urinary sodium excretion rates. The simultaneous administration of ANP and Saline 1 resulted in comparable plasma ANP plateaus in C subjects and HF and NF patients. However, urinary sodium excretion rate was significantly lower in HF and NF patients than in C subjects: HF, 267 +/- 64, P less than 0.01 and NF, 281 +/- 42, P less than 0.01 vs. C, 424 +/- 39 mumol.min-1 x 1.73 m-2. During simultaneous administration of ANP and Saline 1, GFR and FF increased in C subjects, but not in HF and NF patients. HF and NF patients had higher urinary vasodilatory prostanoid excretion rates than C subjects at baseline. Saline infusion did not change urinary excretion rate of prostanoids either in C subjects or IDDM patients (both NF and HF).(ABSTRACT TRUNCATED AT 400 WORDS)

Insulin resistance is associated with high sodium-lithium countertransport in essential hypertension

The nature of the association between essential hypertension and insulin resistance remains unknown. We measured plasma glucose and insulin levels after an oral glucose tolerance test (OGTT), as well as insulin sensitivity (using a euglycemic hyperinsulinemic clamp), glucose turnover (Rd; using [6,6-2H2]- and [3-3H]glucose isotopic dilution), and forearm net balance of glucose (using arterial-venous difference) in 22 hypertensive patients with high (H2) red blood cell (RBC) sodium-lithium countertransport (Na(+)-Li+ CT; greater than 0.41 mmol.l RBC-1.h-1), 21 hypertensive patients with normal (H1) Na(+)-Li+ CT, and 22 normotensive controls (C). After OGTT, H2 patients had higher plasma glucose and insulin levels than H1 and C. During euglycemic hyperinsulinemia (approximately 100 microU/ml) Rd was lower in H2 [21.7 +/- 1.4 (SE) mumol.kg-1.min-1] than in H1 (44.3 +/- 2.9; P less than 0.01) and C (48.1 +/- 3.0; P less than 0.01), and an inverse correlation was found between rates of Na(+)-Li+ CT and Rd in H1 and H2 (rs = -0.76; P less than 0.01). Forearm glucose uptake was 40-50% lower in H2 compared with H1 and C (P less than 0.01). Lactate concentration increased more in C (from 511 +/- 24 to 1,207 +/- 69 microM) and in H1 (from 564 +/- 40 to 1,122 +/- 99) than in H2 (from 581 +/- 42 to 950 +/- 102, P less than 0.05 vs. both). Forearm blood flow increased more in C (31%, P less than 0.05) and H1 (22%, P less than 0.05) than in H2 (12%).(ABSTRACT TRUNCATED AT 250 WORDS)

Impaired response to angiotensin II in type 1 (insulin-dependent) diabetes mellitus. Role of prostaglandins and sodium-lithium countertransport activity

The pathogenesis of diabetic nephropathy remains elusive. A role for renal prostaglandins in antagonizing the hormonal effects of renin-angiotensin II has been postulated as a putative factor leading to hyperfiltration in patients with Type 1 (insulin-dependent) diabetes mellitus. Our aim was to elucidate the effects of angiotensin II on kidney haemodynamics and on blood pressure in eight normal subjects, in nine normotensive, in nine hypertensive with normal sodium-lithium countertransport activity in erythrocytes, in seven hypertensive without and in eight hypertensive Type 1 diabetic patients with microalbuminuria and with high sodium-lithium countertransport activity in erythrocytes. Angiotensin II infusion (4 ng.kg-1.min-1 for 60 min) decreased the glomerular filtration rate to a greater extent in normal subjects (-20%), than in normotensive patients (-5% p less than 0.01), in hypertensive patients with normal sodium-lithium countertransport activity in erythrocytes (-8% p less than 0.01) in hypertensive patients with high sodium-lithium countertransport (-6% p less than 0.01) and in hypertensive microalbuminuric patients (-5% p less than 0.01) with Type 1 diabetes. The urinary excretion rate of vasodilatory prostaglandins was two-three fold higher in all patients than in normal subjects. Acute indomethacin treatment restored a normal response to angiotensin II infusion in normotensive patients, but did not change the renal haemodynamic response in normal subjects. With regard to hypertensive patients with and without microalbuminuria indomethacin treatment restored a normal response to angiotensin II in some but not all patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Treatment of central diabetes insipidus using oral DDAVP. Comparison with intranasal treatment]

The Authors have done a clinical study on the efficacy of desmopressin (DDAVP) tablets in the treatment of central diabetes insipidus in 13 patients who were previously treated with intranasal DDAVP. A comparison has been made between peroral and intranasal forms of DDAVP measuring the urinary volume and osmolarity daily. The right dosage of DDAVP tablets was between 150 and 600 micrograms/die. The patients showed very good compliance during the 4 weeks of treatment with DDAVP.

LHRH-induced gonadotropin release before and after short-term therapy with cabergoline in hyperprolactinaemic patients

Cabergoline is a new ergot derivative with long-lasting PRL lowering effect. Basal and LHRH stimulated (50 micrograms i.v.) gonadotropin secretion was evaluated before and during cabergoline treatment (0.5-2 mg/week) in 28 women with pathological hyperprolactinaemia. After 4 weeks, PRL and E2 were significantly (p less than 0.01) reduced and increased, respectively. Basal LH and FSH levels did not change. Both LH (p less than 0.05) and FSH (p less than 0.02) responsiveness to LHRH was decreased from the former to the latter test. The study underlines drug-induced variations in gonadotropin responsiveness to LHRH which are probably due to variations in the steroid milieu.

Penetration of erythromycin into tonsillar tissue

A study was carried out to investigate serum levels and tonsillar tissue penetration of erythromycin in 80 children suffering from chronic tonsillitis who had to undergo tonsillectomy. Oral erythromycin ethyl succinate (1 g twice daily) was given for the 2 days preceding surgery, the last dose scheduled for 2, 3, 4 or 6 hours before the start of the operation and the withdrawal of blood and tissue samples. The results showed that erythromycin penetrated quickly into tonsillar tissue and the levels were higher in tissue than in serum at all time points. Mean levels of erythromycin were consistently greater than the minimum inhibitory concentrations for most common Gram-positive oro-pharyngeal pathogens and H. influenzae.