The effect of anesthetics on the basal secretion of immunoreactive growth hormone in rats]

The authors investigated basal levels of plasma immunoreactive growth-hormone in the rat (R-GH) after administration of 3 different anesthetic drugs: urethan, chloral hydrate and gamma-hdroxy-butyrate (GHB). Lowest R-GH concentrations (5 +/- 3 ng/ml) are observed after urethan; they are significantly higher (15 +/- 4 ng/ml) after chloral hydrate but this anesthetic also causes hyperglycemia (210 +/- 30 mg/100 ml). Normal blood glucose levels are observed under GHB narco-analgesia which elicits a clear-cut R-GH secretory episode (70 +/- 5 ng/ml); basal values (12 +/- 3 ng/ml) are maintained for several hours thereafter.     

Serum cholesterol levels in a Nigerian population sample

Serum cholesterol was determined in 104 healthy Nigerians (57 males and 47 females). The average cholesterol concentration was 187 +/- 72.8 mg/100 ml (mean +/- SD) with a range of 60-480 mg/100 ml. Cholesterol levels were higher in males than in females and increased with age. Distribution of cholesterol level was generally skew to the left.     

Estimation of systemic catecholamine levels in the frog, using the technic of radio-enzymatic assay]

We have developed a radio-enzymatic assay for systemic catecholamines in the frog. Such are its specificity and sensibility that adrenaline and noradrenaline may be measured in 50 microliter of plasma samples, the withdrawal of which strongly influenced the results. The smaller values were obtained in plasma withdrawn from canulated animals. In this case, adrenaline was the major catecholamine in the plasma: 190 +/- 55 ng/100 ml versus 35 +/- 18 ng/100 ml for noradrenaline.     

Effects of blood sampling, anesthesia and surgery on plasma vasopressin concentration in rats.

The influence of blood sampling, anesthesia and surgery on plasma vasopressin concentration was assessed in rats. Mean plasma concentration in conscious, chronically catheterized rats was 1.4 +/- 0.1 pg/ml (n = 6). This value remained constant over repeated plasma samplings in the same animals. On the other hand, decapitation increased the plasma vasopressin concentration to 6.0 +/- 2.4 (in pg/ml) (n = 6), inactin anesthesia to 2.9 +/- 0.6 (n = 6), anesthesia and femoral cannulation to 13.3 +/- 5.8 (n = 6) and surgery for renal micropuncture to 81.3 +/- 35.0 (n = 6). It is concluded that the level of circulating plasma vasopressin is highly dependent on the sampling technique and is closely related to the extent of surgery.     

Plasma estrogens in Pleurodeles waltlii. Comparison between diploid and triploid females]

Estrogens have been examined in the plasma of diploid and triploid newts Pleurodeles waltlii. Estradiol-17 beta (E2) and estrone (E1) were determined by radioimmunoassay, before and after enzymatic hydrolysis of the conjugates. Total (t) and unconjugated (u) E2 levels were positively correlated (E2u = 0.478 35 E2t + 0.579 98; r = 0.883), but no correlation was detected between E1 levels. No statistical difference was found for the estrogen levels between the different experimental lots of diploid newts (E2t = 7.5 +/- 0.37 ng/ml, E2u = 4.3 +/- 0.20 ng/ml, E1t = 2.19 +/- 0.08 ng/ml, E1t = 0.41 +/- 0.02 ng/ml) but every estrogen level was lower in the triploid group (E2t = 1.8 +/- 0.60, E2u = 1.0 +/- 0.18, E1t = 1.4 +/- 0.13, E1u = 0.3 +/- 0.04 ng/ml). This difference is discussed in relation to lower fertility of the triploid females.     

Effects of 18-hydroxydeoxycorticosterone on central nervous system excitability

The effects of 18-hydroxydeoxycorticosterone (18-OH-DOC) on central nervous system excitability were studied in adrenalectomized rats. Sixty-four evoked potentials (EP) recorded from the pontine reticular formation were averaged before and after the injection of vehicle and hormone. 750 micrograms of 18-OH-DOC dissolved in 0.5 ml of a 4:1 saline Cremophor-EL solution were injected i.v. A decrease of 55.7 +/- 6.1% in the amplitude of the EPs was observed with the hormone 16.3 min +/- 2.7 (SE) after injection. Amplitude values returned to baseline levels 38 min +/- 6.8 (SE) after injection. The secretion of 18-OH-DOC is greatly increased by ACTH and might modulate central nervous system function.     

Action of diphenylhydantoin on chromosomes

The effect of diphenyl hydantoin, (DPH) a nonbarbituate anticonvulsant drug, on chromosomes and fertility was tested in cultured human lymphocytes, mouse fertility, and rat maternal marrow chromosomes and fetal development. Whole human blood from 5 male and 5 female subjects was cultured for 68 hours with phytohemagglutinin, then incubated for 2 hours in isotonic salts with .05-.3 mg per ml DPH, .02 mcg per ml colchicine, or .4 mg per ml sodium diethylbarbiturate. The mean number of metaphases per 1000 stimulated cells was 10.0 in controls, 40.3 with colchicine, 27.9 with diethylbarbiturate, and 30.5 with .25 mg DPH per ml. Both diphenylbarbiturate and DPH produced linear dose effect curves. These results were demonstrated not to be due to urea, since there were no differences in urea content, with a 2 hour urease micromethod. Mouse fertility was totally inhibited in 6 virgin mice given .1mg DPH daily for 10 days compared to 41 pups both of 6 control mice. In 6 pregnant rats given 25 mg DPH per 100 gm/orally 4 times daily for 2 days on gestation Days 7 and 8, there were 5 rats with all fetuses resorbed and 1 rat with 3 living and several resorptions. 6 controls had 6-14 normal fetuses each. 50 metaphase plates from each rat's femoral marrow and each fetus were examined 2 hous after injecting .3 mg colchicine per 100 gm. 30% of the metaphase cells from treated females and fetuses showed strongly contracted chromosomes and reduced number os "pulverized" chromosomes. These phenomena may have been due to inhibition by DPH of folic acid metabolism which is involved in purine synthesis.     

Effect of progesterone on male and female sex behavior induced by steroid hormones in adult ovariectomized ewes]

Ovariectomized adult Ewes daily treated with I/M injections of testosterone propionate (10 mg/day) or oestradiol benzoate (200 microgram/day) show male-like sexual behaviour and simultaneously a permanent female receptivity. Additional daily treatment with 100 mg of progresterone results in a rapid decrease in male sexual responses both when Ewes are treated with testosterone and with oestradiol. No effect is observed on the female receptivity. Cyproterone acetate (100 mg/day) given to Ewes in addition to daily injection of testosterone propionate (10 mg/day) has effects similar to those of progesterone. These results show that progesterone has antiandrogen and antioestrogen properties and that this hormone administered at high doses is able to inhibit male activity.     

Response of serum calcium to administration of an extract from Stannius corpuscles in the anurans

Summary The effect of i.p. injection of an aqueous extract of Stannius corpuscles (10 mg/ml/100 g b.wt) on serum calcium levels was investigated inRana cyanophlyctis andBufo andersonii. This treatment evokes in both species hypocalcemia over a period of 1–4 h, followed by hypercalcemia at 6 h, with a return to control at 8 h.     

Human growth hormone in urine: development of an ultrasensitive radiometric assay

An immunoradiometric assay for human growth hormone (HGH) has been developed which has a detection limit of 1 ng/l and can measure HGH in unextracted urine from normal children and adults. The assay is based on a two-step procedure, using a solid-phase goat-anti-HGH immunosorbent for immunoextraction and [125I]-labeled monoclonal HGH-antibody for detection and quantification. The assay is not affected by urea, NaCl or changes of pH from 5-8. The mean urine HGH concentration in normal children is 6.78 +/- 7.6 (SD) pg/ml, in patients with HGH-deficiency 1.3 +/- 0.9 pg/ml which increases to 11.7 +/- 13.4 pg/ml on the day of growth hormone injection.     

Effects of ethanol and acetaldehyde on cultured pre-implantation mouse embryos

Pre-implantation 2-cell stage mouse embryos, obtained from superovulated CF-1 mice, were exposed to ethanol and acetaldehyde through the culture medium for 60 min followed by a 105-h incubation period. Control and ethanol exposed embryos survived equally well in ethanol concentrations as high as 800 mg/100 ml medium and acetaldehyde levels up to 10 mg/100 ml medium.     

Potentiation of immunologic memory by Corynebacterium parvum and its mechanism]

Immune response to bovine serum albumin (BSA) at dose of 2,50 mg/kg which is rather a weak immunogen in Rabbits, when given intravenous was highly potentiated when the animals received a previous single intravenous infection of 2 mg/kg of C. parvum, followed by subsequent BSA anamnestic challenges for several months. Thus, the antibody amounts synthesized following the 1st anamnestic injection (3 weeks) were 0,260 mg/ml in the control versus, 0,800 mg/ml in the C. parvum pretreated groups; following the 2nd anamnestic challenge (12 weeks afterwards) 1 mg/ml in the control versus, 2,50 mg/ml in the treated groups following the 3rd anamnestic challenge (28 weeks afterwards) 1,3 mg/ml in the control versus 5 mg/ml in the C. parvum pretreated groups; following the 4th anamnestic challenge (52 weeks afterwards) 0,300 mg/ml in the control versus 0,800 mg/ml in the C. parvum treated groups. On the whole for the four first anamnestic challenges the differences at peak levels between the control and C. parvum treated groups were about to 4. Furthermore, the antibody molecules synthesized by the C. parvum treated animals were found to belong to IgG class. The results suggest that the immunological mechanisms mobilized are peculiar to C. parvum since they could not be reproduced either by BCG or by Freun'd adjuvant under similar conditions.     

Effects of ethanol and acetaldehyde on cultured pre-implantation mouse embryos

Summary Pre-implantation 2-cell stage mouse embryos, obtained from superovulated CF-1 mice, were exposed to ethanol and acetaldehyde through the culture medium for 60 min followed by a 105-h incubation period. Control and ethanol exposed embryos survived equally well in ethanol concentrations as high as 800mg/100 ml medium and acetaldehyde levels up to 10 mg/100 ml medium.     

Age distribution of circulating alpha-interferon

A sensitive radioimmunoassay showed that circulating alpha-interferon in the plasma of healthy individuals was low in children and reached the highest level in the young adult, then declined gradually with age. Circulating alpha-interferon was 0.201 +/- 0.059 ng/ml in males (n = 19) and 0.184 +/- 0.076 ng/ml in females (n = 14) at ages 30-39 years old. It was noted that circulating alpha-interferon was maintained up to a certain level even in elderly individuals.     

Dissociation of digoxin-like immunoreactivity and Na+,K+-ATPase inhibitory activity in rat plasma

We measured endogenous digitalis-like factor (EDF) in rat plasma during acute saline infusion by two different procedures. Na+,K+-ATPase inhibitory activity in the rat plasma significantly increased during saline loading (7.8 +/- 2.2 vs 2.5 +/- 0.9%, with and without acute saline loading, respectively, p less than 0.05). On the other hand, the plasma digoxin-like immunoreactivity significantly decreased during acute saline loading (16.9 +/- 1.6 vs 32.0 +/- 2.8 pg digoxin equivalents/ml, with and without acute saline loading, respectively, p less than 0.01). These results indicate that the major substances detected by digoxin-like immunoreactivity and direct Na+,K+-ATPase inhibitory activity are completely different, at least in rat plasma.     

Plasma hormone levels in normal and lead-treated pregnant mice

Summary Dietary lead (0.5%) was given to mice which, after mating, exhibited a vaginal plug. Estradiol, progesterone and prostaglandins E and F 2 were determined in, the plasma by radioimmuno assay at different times thereafter. The increase in estradiol and decrease in prostaglandins prior implantation are not greatly altered by lead treatment, whereas the subsequent increase in progesterone and later in estradiol is abolished. It is concluded that the lower number of pregnancies seen in lead-treated mothers is due to a maternal hormonal imbalance caused by lead.Supported by contract 038-74-7 ENV B of the E.C. Environmental Research Program. Publication No. 1394 of the Euratom Biology Division.     

Effect of hyperkalemia on insulin secretion

The effect of hyperkalemia on insulin secretion remains undefined. We evaluated portal and peripheral insulin levels in anesthetized dogs after infusions of KCl. The mean maximal increase in peripheral plasma potassium at infusion rates of 0.2 mEq/kg/h was 0.68 +/- 0.20 mEq/l. There were no significant increases in either portal or peripheral insulin levels. In contrast, in six dogs whose plasma potassium concentration increased in each case by more than 2.0 mEq/l (infusion rate of 0.5 mEq/kg/h), portal insulin levels increased fivefold (p less than 0.05). We concluded that only marked increases in plasma potassium concentration stimulate pancreatic insulin secretion.     

Serum cholesterol levels in a nigerian population sample

Summary Serum cholesterol was determined in 104 healthy Nigerians (57 males and 47 females). The average cholesterol concentration was 187±72.8 mg/100 ml (mean±SD) with a range of 60–480 mg/100 ml. Cholesterol levels were higher in males than in females and increased with age. Distribution of cholesterol level was generally skew to the left.Acknowledgment. I am grateful to Mr S. O. Oguike an Mr O. Uzoechi for technical assistance. I also thank Dr. E. O. Anosike for his help in arranging for the subjects of study.     

Superoxide dismutase activity in the Spanish population

Superoxide dismutase is an enzyme that catalyzes the dismutation of superoxide radicals to hydrogen peroxide and molecular oxygen. This superoxide radical is produced by all aerobic cells as a normal metabolic intermediate of molecular oxygen, and is dangerous for the cell because it induces the inactivation of various enzymes, lipid peroxidation and mutations. Superoxide dismutase can therefore be considered as a protective enzyme. The purpose of this work was to determine the level of superoxide dismutase activity in the Spanish population, and to study the factors that influence this activity. The superoxide dismutase activity of 2397 individuals was determined using the method described by Minami and Yoshikawa. The superoxide dismutase activity level in the adult Spanish population was found to be 4.16 +/- 0.89 Units/ml of blood. No significant variations with respect to sex were detected. But it was observed that the superoxide dismutase activity level was 9% higher in the young urban Spanish population.     

Hemodynamic studies in a parabiotic model of portal hypertension

Splanchnic and systemic hemodynamic studies were performed in a rat model of parabiosis and portal hypertension. A portal hypertensive and a normal rat were surgically united side to side. A hyperdynamic circulation, characterized by increased cardiac index (413 +/- 26 vs 318 +/- 23 ml X min-1 X kg-1; p less than 0.05) and portal venous inflow (9.61 +/- 1.29 vs 6.33 +/- 0.36 ml X min-1 X 100 g b.wt-1; p less than 0.05), was found in all the portal hypertensive rats but not in the normal parabiotic partners. These results do not support the existence of a transferable humoral factor mediating the hyperdynamic circulatory state of chronic portal hypertension.