Romulo Ribeiro Pieroni

Effects of adrenergic stimulating and blocking agents on glucose-induced insulin responses in human thyrotoxicosis.

Abstract The effects of thyroid hormone excess on insulin responses to a constant glucose infusion ( 300 mg min/60 min ) were studied in five adult thyrotoxic patients with Graves disease before and after they had attained euthyroidism. The tests were also performed during administration of isoproterenol (0.05 μg/kg body weight/min), propranolol (0.08 mg/min) and phentolamine (0.5 mg/min). In the control experiments, to similar plasma glucose, thyroid hormone excess was accompanied by higher fasting plasma insulin, suggesting an insulin resistant state. During glucose infusion, to similar glucose increments, insulin concentration increased in both hyper and euthyroid states, differences in concentration observed in the fasting state disappearing during the infusion, suggesting either reversal of the insulin resistant state and/or decreased insulin responses in the hyperthyroid state. During isoproterenol administration, thyroid hormone excess induced disproportionally higher insulin responses to glucose, suggesting that β-stimulation and thyroid hormone exerted agonistic actions. During propranolol administration, thyroid hormone excess counteracted the β-adrenergic blockade effect in decreasing insulin secretion, suggesting that thyroid hormone and β-adrenergic blockade presented antagonistic effects. During phentolamine administration, apart from its effect by itself, no apparent action of thyroid hormone excess on insulin responses to glucose could be demonstrated. The results suggest that thyroid hormone influences on glucose-induced insulin responses are apparently agonistically interrelated to the β-adrenergic tonus of the patients.

Pathogenesis of Indirect Reacting Hyperbilirubinemia after Portacaval Anastomosis

Summary The previously described peculiar type of hyperbilirubinemia characterized by the predominance of indirect reacting bilirubin which appears in patients who have undergone portacaval shunt was studied in more detail. It was shown that hemolysis plays an important role in its pathogenesis. Disappearance or decrease of hyperbilirubinemia, hyperhemolysis, and cytopenia were observed after splenectomy.

Preparation of high-quality iodine-125-labelled pituitary human follicle-stimulating hormone (hFSH) for radioimmunoassay: Comparison of enzymatic and chloramine-T iodination

A method is described for the enzymatic radioiodination of human follicle-stimulating hormone (hFSH) by a system consisting of lactoperoxidase, hydrogen peroxide and Na125I. It was compared with the Chloramine-T modified technique. A satisfactory specific activity of the labelled hormone was obtained with the enzymatic iodination with much greater immunoreactivity was stability than after Chloramine-T.

An accurate determination of human growth hormone content in different pituitary extracts, using a radioimmunoassay with polyacrylamide gel electrophoresis as a bound-free separation system

Human growth hormone was extrated and purified according to the method of Roos et al. (Roos, P., Fevold, H.R. and Gemzell, C.A. (1963) Biochim. Biophys. Acta 74, 525). A first control of its purification and integrity was performed through molecular weight determination by gel filtration on Sephadex G-100 and on polyacrylamide gel electrophoresis (PAGE). Its biological activity was confirmed by the growth promoted in non-hypophysectomized rats at plateau. The main object, however, was the setting up of accurate, reproducible method tha could furnish the more absolute and comparable values of radioimmunoassayable HGH content in perfect agreement with the results obtained by other laboratories. This was accomplished through a radioimmunoassay system that uses HGH labelled with 125I, where separation of the bound from the free antigen is achieved on polyacrylamide gel electrophoresis, by a modification introduced in the original method of Davis. The resulting values, extremely close to that stated by the KABI-Laboratories (Stockolm), though obtained in quite different conditions of incubation, antibody concentration and with no use of second antibody, represent a confident approach to a comparable measure of this hormone in extracts, which can also be applied to plasma determinations.

Preparation of high-quality iodine-125-labelled pituitary luteinizing hormone for radioimmunoassay

High quality pituitary luteinizing hormone labelled with 125-I was obtained after separating out the more heavily iodinated fractions, through starch gel electrophoresis, using the cathodal component (Fraction 1) which was further purified on Sephadex G-100, giving an almost pure 125-I-labelled luteinizing hormone preparation, presenting excellent immunoreactivity and low levels of damage on incubation in plasma. The quality control of the steps of the technique was done with plasma-coated talc (200 mg) which compared favorably, as far as being an indication of intact labelled luteinizing hormone, with the more time-consuming chromatoelectrophoresis.

Water and Electrolyte Metabolism in Adrenal and Pituitary insufficiency II. Effect of Gluco- and Mineralocorticoid Adrenal Steroids on Sodium Metabolism, with Special Reference to Exchangeable sodium

Abstract Six patients with adrenocortical insufficiency were studied and the data presented demonstrate discrepancies in the results obtained by the classic metabolic Na balance technic, the measurement of exchangeable sodium with Na 22 during steroid withdrawal, and the replacement with aldosterone and/or glucocorticoids. These discrepancies arose frequently enough to suggest that during aldosterone administration some of the retained sodium may be deposited in nonexchangeable stores which may become exchangeable when glucocorticoids are given.

Comparison of plasma progesterone assay in women by competitive protein binding (CPB) and radioimmunoassay (RIA)

Plasma progesterone levels during the follicular and luteal phases were compared when measured simultaneously by competitive protein binding (using guinea pig sera as binding agent) and radioimmunoassay (antiserum against progesterone-11-alpha-succinyl bovine serum albumin in rabbits), the values obtained were significantly different within each technique, depending on whether previous thin-layer chromatographic purification of the extracts was employed or not. No significant differences were noticed between CPB and RIA when the chromatographic step was used, but when it was omitted, CPB was greater than RIA at the follicular but not at the luteal phase.