Preservation of renal compensatory growth in uninephrectomized rats by low-dose cyclosporine.

The growth-inhibitory effect of prednisone is a serious drawback to its use in kidney graft recipients. At high doses, cyclosporine also inhibits somatic growth in animals. Furthermore, cyclosporine, in addition to being nephrotoxic in patients, is reported to inhibit compensatory renal growth in uninephrectomized rats.

Frog brain and liver show evolutionary conservation of tissue-specific differences among insulin receptors.

The insulin receptors of frog brain and liver show features typical of other insulin receptors with regard to affinity and specificity of binding to insulins and proinsulin, solubility in Triton X-100, binding to and elution from wheat germ agglutinin, and insulin-sensitive tyrosine kinase activity. Likewise, the brain and liver receptors differ from one another in electrophoretic mobility and susceptibility to treatment with neuraminidase, analogous to brain and liver receptors of reptiles, birds, and mammals; while the functional implications of these differences are unknown, their evolutionary conservation for 400-500 million years suggests the possibility that they might have importance.

Comparison of verapamil and nifedipine in thrombosis models.

Calcium blockers and calmodulin antagonists have been reported to inhibit the aggregation of blood platelets in vitro. In the present study, the effects of two calcium blockers, verapamil and nifedipine, were compared in several rodent thrombosis models. In rat and mouse platelet-rich plasma, preincubation with either verapamil or nifedipine had a dose-dependent inhibitory effect on collagen-induced aggregation (P less than 0.

Insulin receptors in lizard brain and liver: structural and functional studies of alpha and beta subunits demonstrate evolutionary conservation.

Specific insulin receptors are present in the liver and brain of the lizard Anolis carolinesis. In this study, the specific binding of 125I-insulin to the receptors showed time, temperature and pH dependency. Specific binding to crude membranes prepared from brain was 1-2% of the total radioactivity added compared to 4-5% in the crude membranes prepared from liver.

Plasma cholesterol levels in eviscerated rats.

Eviscerated rat models with a functional liver in which the kidneys or pancreas could be left in situ or removed were used. We found that removal of the gastrointestinal tract leaving the liver and kidneys intact resulted in a significant elevation above normal of the plasma cholesterol. In the absence of the liver, esterified cholesterol is decreased.

Hypotensive response to prostacyclin and 6-keto-PGE1 following hepatectomy in the rat.

Prostacyclin (PGI2) is metabolized to 6-keto-prostaglandin E1 (6-keto-PGE1) which is more stable yet equipotent to PGI2 in lowering systemic arterial blood pressure in the dog. In this study, partial hepatectomy was performed to determine the role of the liver in the vasodepressor response to both intravenously administered PGI2 and 6-keto-PGE1. The magnitude and the duration of systemic hypotensive responses were measured in hepatectomized and sham-operated male Wistar rats following less than maximal, equidepressor doses of PGI2 (0.

Thromboxane agonism and antagonism in a mouse sudden death model.

The effects of the stable thromboxane agonist, U46619, and sodium arachidonate were tested by i.v. injection into male and female mice.

Sexual differentiation of arachidonate toxicity in mice.

Mature male and female mice 50 days of age were challenged with i.v. sodium arachidonate at doses of 12.

Acute protection against arachidonate toxicity by hydrocortisone and dexamethasone in mice.

1. Pharmacologic doses of hydrocortisone sodium succinate (100 mg/kg) has a rapid protective action against arachidonate-induced mortality in mice when administered intravenously 5 to 60 min before intravenous infusion of arachidonate. 2.

Comparison of insulin secretion by the isolated perfused pancreas and perifused islets of the spiny mouse (Acomys cahirinus).

The dynamics of glucose-stimulated insulin release were studied in the perfused pancreas and in isolated perifused islets of spiny mice. The pattern of insulin release induced by an increase of the glucose concentration from 2.8 mM to 16.

Hyperglucagonemia after removal of lower bowel in rats.

Surgical removal of the jejunum, ileum, and colon from rats (LBX) results in greatly elevated levels of plasma immunoreactive glucagon (pIRG) 24 h after surgery (0.98 +/- 0.07 ng/ml, n = 51 vs.

Effect of corticosteroids on arachidonate induced mortality in male and female mice.

Sodium arachidonate (50 mg/kg) given intravenously to male and female mice induces pulmonary emboli followed by respiratory distress and cyanosis. Female mice are significantly more resistant to this treatment than male mice. Cortisone pretreatment for four days to intact mice (10 mg/kg/day/4 days) had a significant protective effect in both males and females against arachidonate toxicity, eliminating the sex difference previously observed.

Half life of injected 125I-insulin in control and ob/ob mice.

The t-1/2 of moniodo 125I-insulin in ob/ob mice and their lean litter mates is 10 min. No difference was found between the two groups. Further, 48 hr of fasting did not alter the t-1/2 in ob/ob mice.

Studies on the extra-hepatic effects of glucagon in the eviscerated rat.

The in vivo effects of glucagon on the metabolism of extra-hepatic tissues have been investigated in eviscerated, functionally hepatectomized rats with intact kidneys. In these animals, even pharmacological amounts of exogenous glucagon did not significantly alter plasma glucose, FFA, or amino acids, compared with saline treatment. The possible secondary release of adrenal catecholamines following such doses of glucagon appeared to be similarly ineffective in increasing the peripheral tissue mobilization of substrates.

Glucose tolerance, plasma and pancreatic insulin levels in zinc deficient rats.

Two experiments were conducted to examine the effect of zinc deficiency on glucose tolerance, and on blood and pancreatic insulin concentrations. In the first study, no significant differences in blood glucose or plasma insulin levels were noted between pair-weighted zinc deficient and zinc sufficient rats after an oral glucose load. In the second experiment, the concentration of pancreatic insulin in pair-fed zinc sufficient rats did not differ significantly from that of zinc deficient rats.

Plasma immunoreactive insulin (IRI) and immunoreactive glucagon (IRG) after evisceration with and without a functional liver.

Fed male Wistar rats were eviscerated by two procedures. The first group of eviscerated rats were left with a nonfunctional liver in situ while the second group were eviscerated by a newer technic, developed in this laboratory, that preserves liver function. The animals were maintained on a regimen of saline and antibiotic treatment, and abdominal aortic blood was drawn at intervals up to seventy-two hours postoperatively from animals with a functional liver and up to six hours postoperatively in those with nonfunctional liver status.

Metabolic studies in eviscerated rats with functional livers.

A new technique is described for evisceration in the rat in which liver function is preserved. These animals lack all known sources of glucagon and insulin and are capable of active gluconeogenesis, urea formation and ketone body production by the liver. Measurements of blood levels of the metabolites of the caloric substrates showed that, unlike the classical eviscerate preparation, these animals maintain high blood glucose, urea and ketone body levels for up to 72 hr as contrasted with the profound decrease in these constituents in the absence of the liver.