No abstract

Background. e exact mechanisms for the development of essential hypertension are not known. Activation of the reninangiotensin-aldosterone system (RAAS) in adipose tissue may represent an important link between obesity and hypertension. is study investigates the effects of oral intake of glucose with and without NaCl on angiotensin II (AngII) and aldosterone in obese and nonobese patients with essential hypertension. Methods. Twenty newly diagnosed untreated essential hypertensive patients and 15 normotensive control subjects matched for age, gender, and BMI were studied. Participants fasted overnight (8-10 hrs), and then each subject took 75 gm glucose alone and with 3 gm NaCl, each dissolved in 250 ml. Subjects were monitored for 2 hours. Half hourly BP, plasma glucose (PG), serum Na + , K + , insulin, AngII, and aldosterone were measured. Subjects were classified into obese (BMI >30 Kg/m 2 ) (11 patients and 8 control) and nonobese (BMI <30 Kg/m 2 ) (9 patients and 7 control). Results. After intake of glucose with NaCl serum, AngII was significantly higher in obese hypertensive patients compared with nonobese patients (P � 0.016). Intake of glucose with NaCl resulted in a significantly higher serum Na in obese hypertensive patients compared with nonobese patients Na (P � 0.009). Serum aldosterone was significantly higher in obese patients (P � 0.03, after glucose; P � 0.003, after glucose with NaCl) and in nonobese patients (P � 0.000 and P � 0.000, respectively) compared with their respective normotensive control subjects. In obese and nonobese patients, intake of glucose and glucose with NaCl showed no significant change in the levels of serum AngII and aldosterone which was associated a significant increase in serum Na in obese patients (P � 0.03) and a highly significant reduction in serum K in nonobese patients (P � 0.001). Conclusion. Failure of suppression or inappropriate maintenance of secretion of AngII and aldosterone in both hypertensive groups by intake of glucose with NaCl may indicate a possible mechanism of essential hypertension.

Departments of Physiology and Pathology, Faculty of Medicine, University of Khartoum, P.O. Box 102, Khartoum, Sudan (Received 31 October 1977) The important role of the kidney in the degradation and excretion of insulin has recently been reviewed (Rubenstein & Spitz, 1968; Rubenstein, Mako & Horwitz, 1975). The kidney functions with a wide margin of safety but the minimum functional renal mass required for the effective elimination of insulin is not known. The present report deals with the effects of total and five-sixths nephrectomy on the concentrations of insulin and glucose in the blood. The effects of uraemia itself, produced by bilateral ureteric ligation, have also been studied. Albino rats of the Wistar strain (mean weight 232 ± 5 (s.e.m.) g) were used. Except for ten female rats included in the acutely uraemic group, the remainder of the animals were male. The subsequent operations were performed under open diethyl ether anaesthesia

Plasma levels of insuilin and growth hormone have been measured over a 6-hr. period in ten normal subjects, (a) fasting and resting, (b) after a protein meal and resting, and (c) after a protein meal followed by 2 hr. moderate exercise. Low levels of insulin and growth hormone were found during fasting and the insulin levels fell further throughout the fast. Hunter, Fonseka and Passmore [1965] demonstrated that moderate exercise in the postabsorptive state was associated with a marked elevation of plasma GH in adults. They also showed that the simultaneous ingestion of protein (casein) increased this response. In the same year, Knopf et al. [1965] and Merimee, Lillicrap and Rabinowitz [1965] reported that large doses of amino acids infused intravenously caused both insulin and GH release.Recently Rabinowitz et al. [1966] reported that the ingestion of a large amount of beef resulted in a small increase in plasma insulin and was associated with GH secretion in a group of normal female volunteers. They also found that the protein when taken with glucose gave a greater insulin response than glucose alone. Knopf et al. [1966] gave large protein meals to healthy volunteers and reported a sequential pattern of release of insulin and GH. They also examined the effect of infusions of individual amino acids.The object of the present study was: (1) to examine the effect of protein alone on hormonal release and (2) to correlate the magnitude and timing of the pattern of secretion of the two hormones when energy expenditure is varied but no exogenous carbohydrate is available. A preliminary report of these studies has already appeared [Sukkar, Hunter and Passmore, 1967].