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Biomedical subjects

K W Taylor

Publications and source records attributed to K W Taylor.

At least 91 records · Page 5Linked to original sources
PubMed1971

The regulation of growth hormone secretion from the isolated rat anterior pituitary in vitro. The role of adenosine 3':5'-cyclic monophosphate.

1. The release of growth hormone from isolated fragments of rat anterior pituitary tissue incubated in vitro was studied by employing a double-antibody radioimmunoassay. 2. In the absence of added stimuli, two phases of hormone release could be distinguished, an early phase of 2h duration and a subsequent late phase. In the early phase, hormone release was rapid but could be significantly decreased by calcium depletion and by 2,4-dinitrophenol whereas the rate of release in the late phase was uninfluenced by these incubation conditions. These results have been interpreted as indicating the existence of a secretory component in the early phase of release. 3. In subsequent experiments, the effects of various agents on the rate of hormone output during the late phase of incubation were investigated. Hormone release was increased by theophylline and by dibutyryl cyclic AMP (N(6)-2'-O-dibutyryl-adenosine 3':5'-cyclic monophosphate), the response to both of these agents being related to the concentration of the stimulant employed. 4. The stimulation of growth hormone output by theophylline was significantly decreased by calcium deprivation and by 2,4-dinitrophenol. The response to dibutyryl cyclic AMP was diminished by 2,4-dinitrophenol, iodoacetate and 2-deoxyglucose but not by malonate or colchicine. 5. Arginine, beta-hydroxybutyrate, albumin-bound palmitate and variation in the glucose concentration of the incubation medium over a wide range were without any statistically significant effect on the rate of hormone release from either control pituitary fragments or those subject to secretory stimulation by dibutyryl cyclic AMP. 6. It is suggested that the regulation of growth hormone secretion is mediated by cyclic AMP (adenosine 3':5'-cyclic monophosphate). The secretion observed in response to cyclic AMP requires the presence of ionized calcium and a source of metabolic energy but is independent of pituitary protein synthesis de novo. The integrity of the glycolytic pathway of glucose metabolism appears to be essential for cyclic AMP-stimulated growth hormone secretion to occur.

Animals↗
PubMed1971

Further studies on streptozotocin therapy for a multiple-hormone-producing islet cell carcinoma.

A patient with a multiple-hormone-producing islet cell carcinoma, who had previously been successfully treated with streptozotocin, was given three further infusions of this drug because of the redevelopment of gastric hypersecretion. Although some evidence of damage to the gastrinsecreting cells was obtained, the fasting plasma gastrin was not significantly altered and the patient died from a perforated duodenal ulcer. Serum insulin levels were considerably reduced and the patient became mildly diabetic but the main complication of treatment was a severe though reversible renal tubular defect. At necropsy considerable quantities of gastrin, but low levels of insulin and glucagon were extracted from a tumour metastasis.

Acetoacetates↗
PubMed1970

Glucose tolerance and serum insulin in identical twins of diabetics.

Glucose tolerance with serum insulin assay has been carried out in 24 apparently unaffected identical twins of diabetics. Glucose values were significantly higher and insulin values significantly lower than in control subjects, but there was considerable individual variation and in half the cases glucose tolerance was normal. There was no case of increased insulin response. In these twins glucose tolerance and insulin response were not correlated with weight, family history of diabetes, age at diagnosis of diabetes in the affected twin, time since that diagnosis, nor with age at testing the unaffected twin. On retesting 12 of the twins after two years no significant differences were found from the first testing.We conclude that not all these twins are likely to develop diabetes, that the assumption that identical twins of diabetics are necessarily "prediabetic" is probably erroneous, and that factors other than genetic ones are important in the aetiology of diabetes.

Adolescent↗