Some characteristics of neutrophils from diabetic patients and their relation to the levels of circulating immune complexes.

In the present work we studied different characteristics of neutrophils from diabetic patients and their relation to the levels of circulating immune complexes (CIC). Twenty-five insulin-dependent (IDD) and 25 non-insulin-dependent diabetic (NIDD) patients were evaluated. Each group was then subdivided according to the presence or absence of microvascular complications (MC). We found that the chemiluminescence (CL) emitted by opsonized zymosan (Zop) stimulated neutrophils in IDD and NIDD patients was significantly increased when compared to healthy subjects (p less than 0.01 and p less than 0.02, respectively). The CL values were correlated to CIC levels and both parameters were related to the presence of MC. On the other hand, the percentage of neutrophils capable of reducing nitroblue tetrazolium was diminished in the two groups of diabetic patients (p less than 0.05 for IDD and p less than 0.01 for NIDD). The percentage of neutrophils with functional C3b receptors was normal in diabetic patients; however, the proportion of phagocytic cells through Fc receptors was significantly decreased in both types of patients (p less than 0.05 and p less than 0.01 for IDD and NIDD, respectively). Furthermore, the number of granulocytes with immune complexes (IC) bound to their cell surface was increased in diabetics. We suggest that the increase of CIC level may produce an increase in IC binding to the neutrophil membrane. These IC could block the Fc receptors, diminish phagocytic capacity and, simultaneously, stimulate the release of toxic oxygen products, thus contributing to produce tissue damage.

On changes in pancreas cytomorphometry, serum insulin and metabolic adjustments induced by long term orchidectomy and substitutive therapy with testosterone in dogs.

Mongrel, male, fasted, unanesthetized dogs under the following alternative treatments: 1) nil, 2) orchidectomy 4 months before the study, 3) orchidectomy 10 months in advance, 4) orchidectomy like in (3) followed by i.m. propylenglycol treatment, 0.05 ml/kg body wt./day, 15 days (vehicle controls, and 5) testosterone hemisuccinate in propylenglycol, 0.75 mg in 0.05 ml/kg body wt./day, for 15 days, were used in this study. Pancreas slices of animals of every group were stained with immunoperoxidase. The animals were fasted, anesthetized for pancreas removal. Pancreatic section mean absorbance was estimated in a Zeiss cytospectrophotometer with a coupled computer. Blood sugar (BS) and both serum, immunoreactive insulin (IRI) and free fatty acids (FFA) were assayed in these.

On changes in pancreas cytomorphometry, serum insulin and metabolic adjustments induced by long term orchidectomy and substitutive therapy with testosterone in dogs.

Mongrel, male, fasted, unanesthetized dogs under the following alternative treatments: 1) nil, 2) orchidectomy 4 months before the study, 3) orchidectomy 10 months in advance, 4) orchidectomy like in (3) followed by i.m. propylenglycol treatment, 0.05 ml/kg body wt./day, 15 days (vehicle controls, and 5) testosterone hemisuccinate in propylenglycol, 0.75 mg in 0.05 ml/kg body wt./day, for 15 days, were used in this study. Pancreas slices of animals of every group were stained with immunoperoxidase. The animals were fasted, anesthetized for pancreas removal. Pancreatic section mean absorbance was estimated in a Zeiss cytospectrophotometer with a coupled computer. Blood sugar (BS) and both serum, immunoreactive insulin (IRI) and free fatty acids (FFA) were assayed in these.

Neuroendocrine changes in female rats born from streptozotocin-diabetic mothers.

In adult female rats born from Streptozotocin-diabetic mothers, blood glucose measured under basal conditions or 30 min after glucose administration was similar to controls; however at 180 min 50% of offspring from diabetics was moderately hyperglycemic whereas 100% of controls were normoglycemic. The time of vaginal opening, and after maturity, the number of rats with regular estrous cycles was in the range of controls. After ovariectomy, control rats receiving estradiol showed a sharp increase of serum LH at 4 pm following progesterone treatment at 10 am, while rats born from diabetic mothers failed to modify serum LH. Estradiol receptors in cell nuclei and cytosolic progestin receptors were determined in anterior pituitary, hypothalamus and preoptic area of rats subjected to a 4-day estradiol treatment. Changes were statistically significant in the hypothalamus only, in that rats born from diabetic mothers showed reduced induction of progestin receptors coupled to increased binding of (3H)-estradiol in cell nuclei. These findings bring support for a hypothalamic defect in rats born from diabetic mothers, the reduction of hypothalamic progestin receptors being reflected in the reduced sensitivity to the positive feedback action of progesterone to release LH.

Metabolic and histological pancreatic changes induced by ovariectomy in the female dog.

The actions of ovariectomy performed 4 months in advance on pancreas cytology and also upon the blood sugar, serum immunoreactive insulin and circulating free fatty acid changes over glucose and insulin tests, were studied in female dogs. We concluded that ovariectomy does not affect blood sugar -basally or during the tests-, glucose space and clearance rate of glucose from circulation. Conversely, the integrated insulinemic response over glucose test was highly risen (956%) by ovariectomy in such animals; the rise occurs despite they show a broadened (59%) insulin space, is slightly mediated by a reduction (132%) in insulin clearance from circulation, and appears to be chiefly mediated by a major enhancement in insulin secretion. The immunocytolocalization of insulin in the pancreatic tissue of ovariectomized female dogs showed hypertrophy of Langerhans islets, beta-degranulation but no vacuolation. However, the piling up of the beta-granules by the vascularly pole of the B-cells as well as the appearance of a pretty number of small islets and microislets widespread over the acini, absent in the pancreatic tissue of the untreated controls in anestrous, indicate for the insulin secretory potency of the pancreas of the ovariectomized female dog to be apparently high. In the female dog, ovariectomy affects serum free fatty acid levels via at least two mechanisms, viz., a) stimulation of lipid storage over the glucose test, and b) reduction in lipomobilization as insulin antagonism predominates.

Metabolic and histological pancreatic changes induced by ovariectomy in the female dog.

The actions of ovariectomy performed 4 months in advance on pancreas cytology and also upon the blood sugar, serum immunoreactive insulin and circulating free fatty acid changes over glucose and insulin tests, were studied in female dogs. We concluded that ovariectomy does not affect blood sugar -basally or during the tests-, glucose space and clearance rate of glucose from circulation. Conversely, the integrated insulinemic response over glucose test was highly risen (956

) by ovariectomy in such animals; the rise occurs despite they show a broadened (59

) insulin space, is slightly mediated by a reduction (132

) in insulin clearance from circulation, and appears to be chiefly mediated by a major enhancement in insulin secretion. The immunocytolocalization of insulin in the pancreatic tissue of ovariectomized female dogs showed hypertrophy of Langerhans islets, beta-degranulation but no vacuolation. However, the piling up of the beta-granules by the vascularly pole of the B-cells as well as the appearance of a pretty number of small islets and microislets widespread over the acini, absent in the pancreatic tissue of the untreated controls in anestrous, indicate for the insulin secretory potency of the pancreas of the ovariectomized female dog to be apparently high. In the female dog, ovariectomy affects serum free fatty acid levels via at least two mechanisms, viz., a) stimulation of lipid storage over the glucose test, and b) reduction in lipomobilization as insulin antagonism predominates.

Metabolic and pancreatic changes caused in male dogs by testosterone chronic administration.

The pancreatic cytology and the glycemic, insulinemic and serum free fatty acid responses in dogs during hyperglycemia induced by glucose and over hypoglycemia evoked by insulin have been studied. The dogs were in the alternative following conditions: untreated, under propylenglycol treatment (vehicle controls) and under testosterone propionate plus its vehicle. Testosterone dose: 0.75 mg/kg body wt./day, once daily. Both intramuscular treatments lasted 2 weeks. In the pancreas of the untreated dogs, the islets presented irregular edges with acute prominences, and B-cells could be clearly appreciated, with a high content of dark brown beta-granules of insulin. B-cells presented negative images of nuclei located in the central areas of such cells. In the pancreas of the testosterone treated dogs, the yellowish cytoplasms of the B-cells looked empty, bearing just a few beta-granules (small amount of stored insulin). The B-cells appear to present a great number of vacuoles in testosterone treated dogs. The curve of glycemia in the glucose and insulin tests, the glucose space and the half-life time of insulin in circulation in dogs under testosterone plus vehicle treatment were similar to those observed in dogs treated with propylenglycol pursuant to the same experimental design used in the other two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Metabolic and pancreatic changes caused in male dogs by testosterone chronic administration.

The pancreatic cytology and the glycemic, insulinemic and serum free fatty acid responses in dogs during hyperglycemia induced by glucose and over hypoglycemia evoked by insulin have been studied. The dogs were in the alternative following conditions: untreated, under propylenglycol treatment (vehicle controls) and under testosterone propionate plus its vehicle. Testosterone dose: 0.75 mg/kg body wt./day, once daily. Both intramuscular treatments lasted 2 weeks. In the pancreas of the untreated dogs, the islets presented irregular edges with acute prominences, and B-cells could be clearly appreciated, with a high content of dark brown beta-granules of insulin. B-cells presented negative images of nuclei located in the central areas of such cells. In the pancreas of the testosterone treated dogs, the yellowish cytoplasms of the B-cells looked empty, bearing just a few beta-granules (small amount of stored insulin). The B-cells appear to present a great number of vacuoles in testosterone treated dogs. The curve of glycemia in the glucose and insulin tests, the glucose space and the half-life time of insulin in circulation in dogs under testosterone plus vehicle treatment were similar to those observed in dogs treated with propylenglycol pursuant to the same experimental design used in the other two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Ovarian dysfunction in streptozotocin-induced diabetic rats.

The effect of streptozotocin diabetes on some ovarian functions in adult rats was examined. Diabetic diestrus animals showed reduced ovary weight and lower circulating levels of progesterone. Scatchard plots of binding data derived from ovarian particulate fractions of normal and streptozotocin diabetic rats revealed the presence of one class of binding sites with high affinity for 125I-hCG. The apparent association constant of the hCG receptors of diabetic ovaries was comparable to that of normal gonads. However, a marked decrease (42%) in the number of hCG binding sites was found in diabetic animals. With isolated luteal cells similar results were obtained, and the administration of insulin to streptozotocin diabetic rats restored to normality the number of hCG binding sites. The maximal response of progesterone production by luteal cells from control ovaries was obtained with 10(-10) M hCG. A 100-fold higher concentration of hCG was required for the maximum stimulation of cAMP synthesis. The cAMP response of cells from diabetic rats was significantly higher than that of control cells. However, luteal cells from diabetic rats showed some loss of sensitivity in the synthesis of progesterone during incubation with hCG. Most of the alterations seen in diabetic female rats could be restored with insulin therapy, indicating that insulin plays an important role in the regulation and maintenance of normal reproductive functions. It is suggested that the diminution of the LH receptor population causes the disruption of normal luteal cell function. This fact could be responsible for some of the reproductive alterations in the diabetic female rat.

Effect of estrogens on blood sugar, serum insulin and serum free fatty acids, and pancreas cytology in female dogs.

We analyzed the changes in blood sugar (BS), serum immunoreactive insulin (IRI), circulating free fatty acids (FFA) and pancreatic cytology caused by estrogenization at low pharmacological dosage in female dogs. Vehicle-injected and untreated controls (anestrus) were studied as well. Neither mean basal BS nor basal serum IRI was modified by the treatments, while the mean basal serum FFA value was raised. Glucose tolerance was not modified by the estrogens while glucose y-mean was significantly raised. Hyperglycemia was higher for a longer time in estrogenized animals compared to both controls, while the profiles of hyperinsulinemia coincided. In the estrogen-treated bitches, the pancreatic B-cells contained scarse brown-stained granules near their vascular pole, as shown by an immunochemical method. In the peripheral part of the pancreas, near the acini, some solitary, poorly beta-granulated B-cells were present. During the IVGTT, serum FFA reached lower values for a longer time in the estrogenized bitches as compared to those found in both control groups. Insulin-induced hypoglycemia in the estrogenized animals coincided with the one evoked in the vehicle controls; in the semilog relationship of serum IRI and time, y-mean was lower than that observed in oil-injected controls, and insulin space was larger. The serum FFA levels of these estrogenized bitches, very high in the basal conditions, did not respond to insulin administration, and were above those found in untreated controls and also in vehicle-injected controls just at the beginning of the test. These results are discussed. We came to the conclusion that estrogenization causes some glucose intolerance in bitches while insulin sensitivity remains normal in the IVITT as studied measuring BS. The glucose intolerance is thought to be related to a reduction in glucose space and occurs despite the normality of the serum IRI response. The pancreas must have an intense secretory response in vivo as as to maintain normal IRI activity despite degranulation of the islets of Langerhans and poor islet hypertrophy and neoformation. The serum FFA changes are thought to contribute towards the tendency to adiposity in these animals.

Nuclear androgen receptors in prostates from diabetic rats.

It is shown that the binding of the synthetic androgen [3H] methyltrienolone ([3H] R1881) to the nuclear fraction of prostates of streptozotocin-diabetic rats is 38% reduced in comparison to controls. Although the exogenous replacement therapy of diabetic animals wih insulin was capable of restoring to normality several body and tissue parameters, the androgen binding capacity of prostate nuclei is not recovered. Normal binding values were observed in diabetic animals which have been treated with exogenous testosterone. It is postulated that the decrease in the nuclear androgen receptor content in the prostatic gland of streptozotocin-diabetic rats is due to the lower circulating testosterone levels in these animals.

Further studies on the effect of cimetidine and other neurotropic drugs on rat serum prolactin.

The hyperprolactinemic effect of H2 histamine receptor antagonists has been described in the rat and in humans. The present study was undertaken to explore more fully the hyperprolactinemic action of cimetidine, and its interrelationship with other neurotropic agents. Adult ovariectomized estrogen-primed rats were injected with mepiramine, diphenhydramine, pilocarpine, atropine, dopamine, cimetidine or saline as control, at different sequences and the effect on serum prolactin was determined. The effect of cimetidine on prolactin release "in vitro" by hemipituitaries of estrogenized male rats during a short time incubation period, was also investigated. Our results indicate that cimetidine is able to release prolactin and that this effect is not prevented by atropine or the classical antihistaminergic agents mepiramine and diphenhydramine. Both pilocarpine and dopamine inhibit the prolactin release due to cimetidine. The hypoprolactinemic action of pilocarpine was completely blocked by atropine, but not by mepiramine or diphenhydramine. Finally, cimetidine was unable to modify significantly the prolactin release by incubated pituitaries. It is postulated that cimetidine acts mainly at the brain and that the hyperprolactinemic effect is not mediated by muscarinic or H1 histaminergic receptors. This action can be prevented by drugs such as dopamine that are able to act on the lactotroph, and also by pilocarpine, probably by stimulating a prolactin inhibiting pathway.

Effect of testosterone on the hypothalamic-pituitary-testicular axis of the old male rat.

Old rats show lower serum testosterone, a lower increase in serum LH either after orchidectomy or after LHRH stimulation, and a lower number of hCG binding sites in testis, compared to younger controls. Treatment with testosterone for 5 to 6 weeks was followed by an increment in the androgen serum levels of about 70% in adult, and of 170% in old animals, a reduction to about one half testicular weight in both groups, and an inhibition of similar magnitudes in the LH increase that followed castration or LHRH stimulation. Testosterone treatment reduced the binding sites for hCG in testis of young rats but did not correct the already low values observed in the old animals. It is suggested that similarities and differences occur in the hypothalamic-pituitary-testicular axis of young and old animals and that differences could be due to changes in set points regulation of the system and/or some intrinsic modification of the hormone producing mechanisms.