Effects of secretin, pancreozymin, or gastrin on the response of the endocrine pancreas to administration of glucose or arginine in man.

Intravenous administration of porcine secretin or pancreozymin or synthetic human gastrin II resulted in raised increments in serum immunoreactive insulin during intravenous infusion of glucose in normal man. Enhancement of serum immunoreactive insulin by each hormone was associated with accelerated disposal of glucose. In response to prolonged intravenous infusion of arginine with pancreozymin there was a maintained rise in immunoreactive insulin and glucagon-like immunoreactivity in the blood. These effects of pancreozymin and arginine were not reproduced with secretin and arginine, and may have been due to the stimulation of glucagon secretion together with insulin by pancreozymin. Enteric infusion of hydrochloric acid, or stimulation of gastric acid secretion by betazole, presumed to cause release of endogenous secretin, led to enhancement of insulin secretion during intravenous infusion of glucose. Enteric infusion of arginine, presumed to cause release of endogenous pancreozymin, led to a rise in serum immunoreactive insulin not attributable to effects of circulating glucose and amino acids. It is concluded that secretin and pancreozymin released in response to physiological stimuli contribute to stimulation of the endocrine pancreas after ingestion of food.

Alteration in intracellular sodium concentration and ouabain-sensitive ATPase in erythrocytes from hyperthyroid patients.

The activity of the ouabain-sensitive sodium-potassium-activated component of the ATP-hydrolyzing enzyme system (ouabain sensitive ATPase) was studied in the erythrocyte membranes of 10 patients with hyperthyroidism, and found to be decreased in all 10 patients. The mean ouabain-sensitive ATPase activity was 43 +/- 4 nmol Pi/mg tissue/h in the patients, compared with 69 +/- 5 nmol Pi/mg tissue/h in the erythrocyte membranes of 10 paired control subjects. The mean concentration of sodium within the erythrocytes was 10.8 +/- 0.9 nmol/liter of red blood cells in the patients and 7.2 +/- 0.3 nmol/liter of red blood cells in the controls. The decrease in ouabain-sensitive ATPase activity did not appear to be associated with a change in the ligand sensitivity of ATPase, nor was there a difference in the activity of the ouabain-insensitive component of ATPase. Serial studies to follow the effects of treatment of hyperthyroidism on red cell membrane ATPase were performed repeatedly in one of these patients. There was a significant inverse correlation between L-thyroxine (T4) and ouabain-sensitive ATPase, as both variables returned to normal. Normal erythrocyte membranes were assayed for ATPase activity in the presence of varying concentrations of L-triiodothyronine (T3) and T4, and following pre-incubation with T4. No significant effect on erythrocyte membrane ATPase was demonstrated in either series of experiments. It can be concluded from these studies that the decreased sodium efflux in the erythrocytes of patients with hyperthyroidism is associated with a decrease in the activity of the ouabain-sensitive component of ATPase in the erythrocyte membrane. The failure to reproduce this effect in vitro suggests that it does not represent a direct effect of the thyroid hormones on the mature erythrocyte membrane.

Limitation of joint mobility (cheiroarthropathy) in adult noninsulin-dependent diabetic patients.

Joint mobility was assessed in 80 consecutive adult noninsulin-dependent diabetic (NIDD) patients and 47 nondiabetic controls matched for age and sex. Impairment of mobility was observed in 36 NIDD patients but only 7 controls (p less than 0.01). There was no significant differences between diabetic patients with and without impaired mobility with regards to age, duration of diabetes, mean daily insulin dose, or overall diabetic control as assessed by the measurement of glycosylated haemoglobin (HbA1C). However, NIDD patients with impaired joint mobility had a significantly increased frequency of microvascular disease, as shown by retinopathy and/or nephropathy (42% versus 22%, p less than 0.05), were more often on insulin treatment (86% versus 63%, p less than 0.05) and more frequently had additional rheumatic disorders such as Dupuytren's contracture and osteoarthritis (36% versus 18%, p less than 0.05). In addition tight waxy skin over the phalanges was commonly associated with impaired mobility (58% versus 22%, p less than 0.01). Limitation of joint mobility was most prominent in the hands but caused no functional impairment. This finding may be an additional marker of microvascular disease in the adult diabetic patient.