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Biomedical subjects

W A Stubbs

Publications and source records attributed to W A Stubbs.

35 records · Page 2Linked to original sources
PubMed1979

The effect of lisuride hydrogen maleate, an ergot derivative on anterior pituitary hormone secretion in man.

The effects of single oral doses of 0.2 mg of lisuride hydrogen maleate, a semisynthetic ergot derivative, on serum levels of prolactin (PRL), growth hormone (GH), thyroid stimulating hormone (TSH), luteinizing hormone (LH), follicle stimulating hormone (FSH), cortisol and blood glucose were studied in six normal males. Lisuride effectively inhibited basal PRL secretion as well as the PRL response to TRH given 3 h later. In addition, the drug raised basal GH levels and decreased basal and TRH stimulated TSH secretion. No significant differences between lisuride and control were observed in basal LH and FSH, LHRH stimulated gonadotrophins or in cortisol. Drowsiness was noted by all subjects, one became nauseated and another vomited, 60 and 90 min respectively after administration of lisuride. No changes were seen in pulse rate and blood pressure. The endocrine effects of lisuride were attenuated by the prior administration of the dopamine antagonist metoclopramide. These results suggest that lisuride acts as a long-acting dopamine agonist and that therefore this drug could be of therapeutic use in hyperprolactinaemic states and acromegaly.

Adult↗
PubMed1979

Effects of the H2 receptor antagonist cimetidine on pituitary hormones in man.

The effects of the histamine (H2) receptor antagonist cimetidine on serum levels of prolactin (PRL), growth hormone (GH), thyroid stimulating hormone (TSH), luteinizing hormone (LH), follicle stimulating hormone (FSH) and cortisol were studied in five normal males. Cimetidine, when given by infusion at the dose of 100 mg/h for 5 h, did not alter adenohypophyseal secretion either basally or after pituitary stimulation with LHRH and TRH. However, 400 mg cimetidine given intravenously as a bolus injection significantly stimulated PRL release in all subjects, without affecting any other measured hormone. A dose-reponse relationship existed, and 200 mg cimetidine seems to be the minimum PRL-releasing dose when given as an intravenous bolus injection. These results suggest that cimetidine releases PRL and that this effect is dose-related, but only when large intravenous injections are given.

Adult↗
PubMed1979

Metabolic studies during normoglycaemic clamping of insulin-dependent diabetics using a glucose-controlled insulin infusion system.

Metabolic rhythms have been studied in six insulin-dependent diabetics during subcutaneous insulin therapy, and during control of blood glucose concentration by a glucose-controlled insulin infusion system (GCIIS). In none of the subjects was blood glucose concentration consistently within the normal range during subcutaneous insulin therapy. In contrast, blood glucose concentration was within the normal range after 3.5 h of insulin delivery by the glucose-controlled insulin infusion system and remained in the normal range for the following 8 h through lunch and dinner. Mean blood glucose concentration during this time ranged from 5.31 to 7.90 mM. Following normalisation of blood glucose concentration, blood lactate and pyruvate were similar with both the GCIIS and subcutaneous insulin therapy. Post-prandial lactate peaks were delayed with the GCIIS. Alanine levels were consistently higher during control with the GCIIS compared with subcutaneous therapy, while blood ketone body and plasma NEFA levels were lower, and the premeal peaks in the lipid metabolites were delayed. It is not possible to conclude that attainment of normoglycaemia with the present generation of glucose-controlled insulin infusion systems in insulin-dependent diabetics is accompanied by total normalisation of intermediary metabolism.

Adult↗
PubMed1978

Hormonal and metabolic responses to an enkephalin analogue in normal man.

An enkephalin analogue [D-Ala2, MePhe4, Met(o)-ol] enkephalin (DAMME), given intravenously to normal subjects raised serum prolactin and growth-hormone levels but lowered serum levels of luteinising hormone, follicle-stimulating hormone, cortisol, and corticotrophin. There was also a small fall in total glucagon and gastric inhibitory peptide (G.I.P.) and a rise in thyrotrophin. beta-Lipotrophin, motilin, vasoactive intestinal peptide, insulin, gastrin, and pancreatic glucagon were unchanged. Blood-glycerol increased, and blood lactate, alanine, and glucose fell. Prior administration of the opiate antagonist, naloxone, attenuated the hormonal responses to DAMME. This enkephalin analogue produces endocrine and metabolic changes in man which may be mediated through opiate-binding receptors both within and outside the brain. The enkephalins and related substances may provide an important link between perception, behaviour, and neuroendocrine regulation of hormone secretion and metabolism.

Adrenocorticotropic Hormone↗
PubMed1977

The effect of insulin on lung metabolism in the rat.

A new model has been established for the perfused in situ rat lung. During perfusion with glucose at 4 mmol/l, physiological concentrations of insulin (50 mu/l) caused an initial 1.5 fold increase in lactate production; the increase being sustained at 30% for the 4 h of perfusion. The observation that the lung responds to physiological concentrations of insulin could have important implications with respect to whole body carbohydrate metabolism.

Animals↗
PubMed1976

Carbohydrate metabolism in cardiovascular disease.

Carbohydrate metabolism is temporarily disturbed in acute myocardial infarction. The degree of hyperglycaemia and failure of response of insulin appears to be related to the severity of the infarction. The underlying hormonal changes probably include increased secretion of catecholamines and of glucagon. Circulating free fatty acids (FFA) are generally increased by the same metabolic and hormonal factors which promote glucose intolerance. In the zone of developing infarction in the heart, there is a complex metabolic situation with glucose metabolism both being accelerated and inhibited by different factors. Continued uptake of FFA is associated with intracellular accumulation of activated long-chain FFA, acyl CoA, which tends to inhibit mitochondrial metabolism. The metabolism of glucose is thought to be beneficial and that of FFA detrimental to the infarcting tissue. Thus the glucose intolerance and the high circulating FFA occurring as part of the general metabolic response to myocardial infarction, are thought to be harmful to the ischaemic tissue. Increased provision of glucose by dichloroacetate, and inhibition of FFA metabolism by nicotinic acid analogues decrease the extent of experimental infaraction, while glucose--insulin--potassium and propranolol act both by increasing glucose uptake and decreasing that of FFA. Glucose intolerance is also common in peripheral vascular disease. The reasons for this are obscure. However, the alterations in circulating insulin concentration which accompany this intolerance may be involved in the development of arterial lesions either directly through an effect on arterial wall synthesis or indirectly through an effect on circulating lipid levels. Defects may also be found in arterial wall mucopolysaccharide or sorbitol metabolism. The role of sex hormones and catecholamines remains speculative. At present the most cogent view is that in peripheral vascular disease a multi-hormonal disorder exists which may be contributing to the development of arteriosclerosis.

Acute Disease↗