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Biomedical subjects

J P Filkins

Publications and source records attributed to J P Filkins.

At least 55 records · Page 3Linked to original sources
PubMed1979

Increased insulin responsiveness in endotoxicosis.

The relation of endotoxicosis to insulin responsiveness was evaluated in male Holtzman rats. Salmonella enteritidis lipopolysaccharide at 0.5 or 1.0 mg per 300 g rat increased lethality in convulsive seizure deaths to 0.25, 0.50, or 1.0 U insulin sc. The hypoglycemic nadir induced by 0.05, 0.10, or 0.25 U of insulin sc was greater in rats rendered endotoxic with 1 mg of lipopolysaccharide IV. Oxidation of U-14C-D-glucose to 14 CO2 by endotoxic tissues in vitro was augmented in liver slices, epididymal fat pads, hemidiaphragms, and spleen slices; no pronounced glucose oxidation increases occurred in lung, heart, stomach, cerebrum, kidney, or whole blood. Epididymal fat pads from endotoxic rats (100 g) manifested increased basal glucose oxidation as well as an enhanced maximal response to incremental insulin doses of 0.01 to 25 mU/ml. It is suggested that altered tissue responsiveness in concert with hyperinsulinemia underlie the profound alterations in glucose homeostasis during endotoxicosis.

Animals↗
PubMed1979

Effect of traumatic injury on sensitivity to insulin.

Disturbances in carbohydrate homeostasis are metabolic hallmarks in the host response to trauma. Since alterations in insulin responsiveness, especially insulin resistance, have been related to the metabolic sequelae of shock, the present study evaluated insulin responsiveness in traumatic shock. Injury (LD50) of fasted, male Holtzman rats (115 plus or minus 20 gm) by tumbling in the Noble-Collip drum resulted in hyperglycemia in spite of a concomitant hyperinsulinemia. The ability of insulin to lower plasma glucose was evaluated at either three hours or 24 hours post-trauma by means of glucose and insulin tolerance tests. The injured rats showed glucose intolerance and hyperinsulinemia three hours after injury but showed a normal glucose tolerance and hypoinsulinemia on the day after injury. Insulin was ineffective in lowering plasma glucose at both of these times. Noble-Collip tumbling trauma induced no systemic changes in insulin responsiveness in vitro at either time as evaluated by 1) epididymal fat pad glucose oxidation of U-D-14C-glucose to 14CO2 or 2) hemidiaphragm incorporation of U-D-14C-glucose into glycogen. The data suggest that insulin resistance is not due to a decreased capacity of various tissues to respond to insulin.

Adipose Tissue↗
PubMed1978

Dexamethasone antagonism of glucose dyshomeostasis in endotoxin shock.

Dexamethasone acetate (100 microgram IP) protected male Holtzman rats (300-330 gm) against endotoxin shock due to Salmonella enteritidis lipopoly-saccharide B IV. Endotoxin (5.0 mg/rat) produced hypoglycemia within 180 minutes, ie, plasma glucose fell from 87 to 24 mg/dl; dexamethasone prevented the hypoglycemia, ie, plasma glucose levels were 129 mg/dl at 180 minutes after endotoxin. Dexamethasone antagonized both endotoxin-induced depression of hepatic gluconeogenesis and enhanced glucose oxidation as evaluated in vivo. Epididymal fat pads from endotoxic rats (100-110 gm) had increased rates of glucose oxidation as evaluated by the in vitro conversion of 14C-D-glucose to 14CO2. Dexamethasone both in vivo and in vitro antagonized endotoxin glucose hypercatabolism by isolated epididymal fat pads following administrated of endotoxin. Glucocorticoid protection against endotoxin shock is related to antagonism of glucose dyshomeostasis.

Adipose Tissue↗
PubMed1977

Protection against endotoxin shock and impaired glucose homeostasis with ATP.

ATP-Mg++ (10 mumoles/100 g, iv) increased the LD50 for Salmonella enteritidis lipopolysaccharide (endotoxin) in male Holtzman rats (300 +/- 10 g) from 1.3 to 6.0 mg/rat. While endotoxin at 3 mg/rat iv 5 hr previously induced hypoglycemia to 12 +/- 4 mg/dl, ATP cotreatment blunted the hypoglycemia; i.e., plasma glucose values were 78 +/- 6 mg/dl. ATP treatment prevented the depression in gluconeogenesis induced by endotoxin as evaluated in vivo by the conversion of 14C-alanine to 14C-glucose. ATP treatment also reduced the hypercatabolism of U-14 C-glucose to 14CO2 in vivo and by epididymal fat pads in vitro. A role for ATP in preventing disruption of glucose homeostasis and development of endotoxin shock via counteracting insulin is suggested.

Adenosine Triphosphate↗
PubMed1976

Bioassay of endotoxin clearance in vivo and by perfused rat liver.

Endotoxin clearances in vivo and by the isolated perfused rat liver were evaluated via bioassay in lead-sensitized rats. A linear relationship between the probit of shock lethality and the endotoxin dose in the probit range of 4-6 was validated. Endotoxin clearance in normal, fed rats displayed a linear relationship between the logarithm of the blood endotoxin concentration and time throughout the period of 15-240 min at doses of 500 and 1,000 mug/ rat; the half-time values were 58-63 min. Decreasing the endotoxin dose to 250 mug resulted in multiphasic clearance curves. Induction of tolerance to endotoxin resulted in marked acceleration of endotoxin clearance. Endotoxin clearance from the isolated perfused rat liver was not influenced by serum or rat blood as compared to clearance from a balanced salt solution. These data suggest that a physiologically stressful dose of endotoxin is slowly cleared from the blood and, therefore, circulates for prolonged periods.

Animals↗
PubMed1976

Hypoglycemic depression of RES function.

The intravascular removal rates of colloidal carbon and of biologically active endotoxin by the reticuloendothelial system (RES) were evaluated as a function of blood-glucose levels. There was a significant negative correlation of carbon clearance half time on blood glucose in both saline-treated and insulin-treated rats. Insulin hypoglycemia depressed RES carbon clearance with the maximal effect occurring at blood glucose values below 30 mg/dl. Insulin hypoglycemia also severely impaired the intravascular removal of endotoxin as evaluated by lethality bioassay in lead-sensitized rats. It is concluded that blood glucose may modulate RES phagocytic function and that the hypoglycemia of endotoxin shock may augment the shock state due to impairment of RES host defense clearance functions.

Animals↗