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Biomedical subjects

M Oprescu

Publications and source records attributed to M Oprescu.

At least 55 records · Page 3Linked to original sources
PubMedDate not supplied

Serum and pituitary prolactin variations under the influence of pyridoxine and pimozide in the male rat.

Prolactin was measured in the serum and hypophyses of the male rat after six days of i.p. administration of pyridoxine 5 mg (group B6), after a single dose of pimozide 2.5 mg/kg body (group PMZ), six days of pyridoxine and one dose of pimozide (group B6- PMZ) and a single dose of tartaric acid (controls). Both pyridoxine and pimozide increased the serum prolactin: 59.06 +/- 16.23 ng/ml and 68.45 +/- 10.78 ng/ml respectively (X +/- DS) by comparison to controls: 33.12 +/- 11.16 ng/ml, their effect being cumulative (83.75 +/- 13.86 ng/ml). However, the effect of pyridoxine and pimozide at the central level is different, pyridoxine producing an increase of the pituitary concentration of prolactin, while pimozide depleted the stored prolactin. Hypothetical mechanisms of pyridoxine action at the pituitary level are discussed.

Animals↗
PubMedDate not supplied

RIA measurement of insulin antibodies in human sera using the polyethyleneglycol separation technique.

A radioimmunological method for the detection and measurement of insulin antibodies in human sera was developed using polyethyleneglycol (PEG) as separation agent. Studies were performed on 150 sera of nondiabetic subjects and on 27 sera collected from diabetic patients treated with insulin. The per cent binding of 125I-insulin in normal sera ranged similarly to control free-insulin serum while in sera from insulin-treated patients8 the binding was significantly greater. The technique is quick (24 hours) and the intra-assay precision (correlation coefficient for replicates) varies from 0.87 to 0.99%. The separation technique using PEG for the precipitation of the antigen-antibody complexes may be extended to the measurement of antibodies for any other substance of lo, molecular weight (under 10,000 daltons).

Antigen-Antibody Complex↗
PubMedDate not supplied

High level of human growth hormone (HGH) in cerebrospinal fluid patients with pituitary tumors.

Six patients with suprasellar extension of pituitary HGH-secreting tumors showed the cerebrospinal fluid (CSF) content in human growth hormone (HGH) to be very high, i.e. 164.3 +/- muU/ml (mean +/- SEM) (range 8.4--413.8 muU/ml) as compared to ten patients with uncomplicated acromegaly whose values were 50-fold lower, i.e. 3.4 +/- 0.5 muU/ml (range 0.6--7.0 muU/ml), and nine patients with suprasellar extension of other pituitary tumors, showing also low levels of HGH in the CSF, i.e. 2.9 +/- 0.8 muU/ml (range 0.6--7.2 muU/ml). A control group of 29 normal patients without pituitary or brain diseases showed extremely low values of HGH in the CSF (1.9 +/- 0.2 muU/ml), one third being below the sensitivity limit of the assay method. Another control group of 70 patients with hypothalamic diabetes insipidus (n = 18), brain traumatisms (n = 10), brain surgery (n = 20), as well as various brain diseases (n = 22), also showed low HGH levels in the CSF, like the normal control group. It is shown that a high level of HGH in the CSF has a potential usefulness in the diagnosis of suprasellar extension of the pituitary mass in acromegaly.

Acromegaly↗
PubMedDate not supplied

The hormonal pattern in alcoholic disease. I. Luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone.

The study included 48 male chronic alcoholics, aged 20 through 50 years, classified in two groups according to the presence (22 patients) or absence (26 patients) of clinically evident sexual disorders. The blood samples were collected the first 2-3 days after hospitalization, before any anti-alcoholic treatment. The control group included 10 adult male normal subjects. By comparison to the control group, the basal level of LH was significantly (p less than 0.01) lower in both groups of alcoholic patients while the FSH level was significantly higher (p less than 0.01) in the group with sexual disorders. The serum levels of testosterone were increased (p less than 0.05) only in the group having sexual disorders. Our data suggest that the feedback regulation of the hypophyseal LH release seems to be impaired by defects in the peripheral metabolization of testosterone.

Adult↗
PubMedDate not supplied

Studies on the action of pesticides upon the endocrines using in vitro human thyroid cells culture and in vivo animal models. I. Herbicides--aminotriasole (amitrol) and atrazine.

The action of aminotriasole (amitrol) and atrazine in doses of 0.001--1 mg and 0.0001--.01 mg/1.5 ml medium, respectively, upon cell cultures of human thyroid was studied in order to find out their influence on cell multiplication, proteic synthesis, enzymatic activity of thyroid cells, and hormonal synthesis. The results varied according to the dose utilized and the type of thyroid cell studied. The acute experiment carried out on rats treated 15 days with 500 ppm amitol and 50 ppm atrazine revealed variations in the T3, T4 and LH synthesis. Amitrol showed a strong inhibitory action on T3 and T4 secretion, whereas atrazine stimulated it.

Amitrole↗
PubMedDate not supplied

The radioimmunological measurement of thyroglobulin secretion in vitro under the influence of some herbicides.

A radioimmunoassay (RIA) technique of human thyroglobulin (Tgl) was developed using 125I-Tgl and a rabbit anti-Tgl serum at the initial dilution of 1:100,000. The sensitivity of the technique was of 2.5 ng/ml. The RIA of Tgl was applied as a screening test for the in vitro secretory activity of human thyroid cells under the influence of two herbicides of the heterocyclic group (Amitrol and Atrazin). Three levels of concentration of Amitrol and Atrazin were administered to the tissue culture tubes containing in the first series of experiments perinodular tissue (Typ), and in the second one nodular tissue (TyN). The thyroid gland was surgically obtained from a patient with the diagnosis of polynodular goiter. Only the high levels (10 mg and 1.0 mg/tube, respectively) of herbicide concentration inhibited the secretion and release of Tgl, the nodular tissue being more resistant to the toxic. However, parallel studies including the dosage of the active hormones (T3, T4) are necessary in order to appreciate the value of Tgl determination as an indicator of hormogenesis in this type of experiments.

Amitrole↗
PubMedDate not supplied

The action of chlorpromazine upon the serum and hypophyseal levels of prolactin and TSH in the pinealectomized male rat.

The action of chlorpromazine (CPZ) administered intraperitoneally (i.p.) in a single dose of 1.0 mg (0.2 ml) upon the serum and hypophyseal levels of prolactin and TSH was investigated in sham-operated (Sh-O) and pinealectomized (Px) male rats. Fourteen days after surgery the animals received 0.2 ml of CPZ or 0.2 ml of isotonic natrium chloride solution and were killed one hour after. The following data were obtained: a) CPZ released pituitary prolactin in both Sh-O and Px groups; b) The TSH circulating levels were increased in the Px group receiving CPZ (p less than 0.01); however, the same sense of variation was observed also in the Sh-O group. The results are suggesting the lack of intervention of the pineal in the mechanism of action of CPZ on the pituitary hormones with or without target gland.

Animals↗
PubMedDate not supplied

The action of chlorpromazine upon the serum and hypophyseal variations of growth hormone, prolactin and TSH in the male adult rat under continuous-lighting stress.

The influence of chlorpromazine (CPZ) on the serum and hypophyseal levels of growth hormone (GH), prolactin and TSH was studied in the male adult rat occurring under normal light-dark-rhythm conditions and under continuous 24-hour lighting, respectively. The serum and hypophyseal concentrations of GH decreased significantly (p less than 0.01 and p less than or equal to 0.02) one hour after the administration of 1.0 mg of CPZ in the animals under continuous light by comparison with the animals maintained on the same conditions. In the animals under normal light-dark rhythm, CPZ did not influence the peripheral or central concentrations of GH. The animals maintained either in normal or in continuous lighting conditions released prolactin under the influence of CPZ. The increased values of circulating TSH in light-exposed animals by comparison with the diurnal group (p less than 0.001) were some more augmented under the influence of CPZ, while this drug remained unefficient in the animals under normal light-dark-rhythm conditions. The mechanism of CPZ action upon the secretion of GH and prolactin, which are hormones lacking target gland, is discussed.

Animals↗
PubMedDate not supplied

Comparative study of the effects of lisuride and pimozide on the preovulatory surge of FSH, LH and prolactin in rat.

In experiments conducted on adult female Wistar rats, lisuride hydrogen maleate, injected before the critical period of proestrus (between 11 h-13 h) in a single s.c. dose of 0.125 mg/kg body, significantly elevated the preovulatory gonadotropin surge and slightly, non-significantly lowered that of prolactin (assessed between 15-16 h). Pimozide, a selective antidopaminergic neuroleptic, injected according to the same schedule in a dose of 2.5 mg/kg body, strongly augmented the LH surge and also prolactin secretion. Thus, stimulation of gonadotropin secretion by lisuride cannot be ascribed to its dopaminergic agonistic action, but may be attributed to its antiserotoninic activity or to the action on the presynaptic dopamine receptors of the tuberoinfundibular neurons, reducing their inhibitory influence on the gonadotropin surge. The results plead for the inhibitory role of DA in the LH and prolactin secretion; 5-HT may have a similar action in the preovulatory gonadotropin surge and a stimulatory one in the surge of prolactin.

Animals↗
PubMedDate not supplied

Bromocriptine treatment of pituitary adenomas. Evaluation of withdrawal effect.

Forty patients wtih pituitary adenomas, i.e. 22 prolactinomas, 13 acromegalies, 5 non-secreting adenomas, were submitted to bromocriptine therapy 19.3 +/- 1.7 mg/day (mean +/- SEM) (range 7.5-40.0 mg/day) for 5 to 41 months (10.1 +/- 1.31). Remission of the tumoral mass was documented by air tomograms (PETG) or computerized tomograms (CT) in all but one prolactinomas and in 2 mixed HGH and PRL-secreting adenomas. Six empty sella syndromes (ESS) were produced, 4 of them during primary chemotherapy. Serum PRL decreased to normal in all but 3 prolactinomas, and serum HGH levels in 5 out of 13 acromegalies. Bromocriptine withdrawal was followed by a rapid increase of serum PRL into the pathological range, without a rapid reexpansion of the tumoral remnants: GT or surgical exploration of 4 cases, remitted until ESS showed a minimal evolution along 8 months after bromocriptine withdrawal. It is suggested that the antitumoral effect of bromocriptine is specific to lactotrophic cells and at least partially irreversible.

Acromegaly↗
PubMedDate not supplied

Inhibition of pituitary-testicular axis response to gonadotropin releasing hormone by pineal treatment.

Purification by ultrafiltration of the pineal extract with antigonadotropic activity enabled us to obtain two fractions, one above 10,000 daltons molecular weight and one below. Administration of these two fractions to intact or castrated rats showed a dissociation of their activity, namely, the larger fraction proved to be anti-LH and the smaller one anti-FSH, as also demonstrated by the specific biologic tests of these hormones. Pineal pre-treatment of the intact and castrated rats whose pituitary had been stimulated with gonadotropic releasing hormone (GnRH) showed that both fractions lower significantly LH and FSH serum levels in both groups of animals. The pineal treatment inhibited the pituitary response to GnRH both in the intact and castrated animals.

Animals↗
PubMedDate not supplied

Inhibition of pituitary response to gonadotropin releasing hormone by urinary gonadotropin inhibiting substance.

The effect of the partially purified urinary gonadotropin inhibiting substance (GIS) on pituitary response to stimulation with gonadotropin releasing hormone (GnRH) was studied. The biologic control of the purified substance showed that the anti-LH and anti-FSH activity of the crude urinary substance was preserved. The experiments made on intact and castrated rats previously treated for two days with GIS and stimulated with GnRH revealed that this substance caused a significant decrease in the serum level of LH and FSH but not in their pituitary content. Furthermore it lowered serum and testicular testosterone in the intact lot as against the controls. The mechanism of action of the purified urinary substance on the pituitary-testicular axis is discussed.

Animals↗
PubMedDate not supplied

The thyroglobulin variations during the thyroid surgery for polynodular goiter, hyperthyroidism and cancer.

A radioimmunoassay (RIA) double antibody system for human thyroglobulin (Tgl) was developed with a sensitivity of 2.5 ng/ml T3 and T4 did not interfere in the antibody Tgl binding. The blood was collected pre-, intra- and 24 hrs post-thyroidectomy from 50 females and 4 males diagnosed as polynodular goiter, hyperthyroidism, chronic thyroiditis and thyroid cancer. The ratios of the intra- and post-operatory values versus pre-operatory values were calculated. The basal values in the patients having thyroid troubles varied within very large limits (two orders of magnitude) and these values could not be clearly correlated to the thyroid pathology, However, in untreated hyperthyroid patients the basal values exceeded 100 ng/ml, while in medullary carcinoma they were near the sensitivity limit of the technique. The intra-operatory values varied within the percentual area (thyroid carcinoma), multiplicative area (polynodular goiter and some cases of hyperthyroidism) and the order of magnitude area (hyperthyroid patients and some of the polynodular goiters). The value of the RIA measurement of the Tgl in the serum as an adjuvant in the post-treatment follow up of thyroid patients is discussed.

Female↗
PubMedDate not supplied

The effect of pineal treatment and pinealectomy on prolactin in rats.

Administration of melatonin-free pineal extract in doses of 2 ml/day/animal along 3 or 7 days caused a statistically significant decrease in the rat serum prolactin level by 28 and 25% respectively, as against the controls. Pinealectomy caused a statistically significant increase in the serum prolactin level by 34% as against the intact controls and by 30% as against the sham-operated ones. The authors discuss their completely oposite results and the role of the pineal gland on prolactin.

Animals↗
PubMedDate not supplied

Mixed TSH- and HGH-secreting pituitary adenoma.

A man aged 36 was found to have an invasive pituitary adenoma with evolutive acromegaly and hyperthyroidism and a high serum level of HGH and TSH, suggesting a tumoral production of HGH and TSH. The serum concentration of HGH was above 180 ng/ml; there was also an inappropriately high serum level of TSH, which failed to decrease following the triiodothyronine suppression test and did not increase after TRH (0.4 mg i.v.). In the tumoral tissue removed during pituitary surgery, the concentration of TSH was 1,267.2 microU/g and that of HGH was 1,158.6 micrograms/g, showing that the pituitary adenoma secreted both TSH and HGH.

Acromegaly↗
PubMedDate not supplied

Additional antitumoral effects of bromocriptine and radiotherapy in patients with prolactinomas or acromegaly.

Thirteen patients with prolactin-secreting and/or growth hormone secreting pituitary tumours have been treated with bromocriptine in doses of about 10 mg/day for several months. Nine of these patients were previously submitted to external or interstitial radiotherapy and one case to pituitary microsurgery. Serum prolactin concentration in patients with prolactinomas was still very high within one year after pituitary irradiation or operation, i.e. 5,125.6 +/- 974 mU/l (mean +/- SEM). It has been reduced to normal level only during bromocriptine therapy, i.e. to 329.1 +/- 88mU/l (p less than 0.001), and increased thereafter, but remained to a significantly lower concentration than before bromocriptine treatment, i.e. 2,709.0 +/- 553 mU/l (p less than 0.05). Serial pneumonecephalotomography has demonstrated the reduction of tumour size afrer bromcriptine therapy to two prolactinomas with suprasellar extension. In patients with acromegaly the effects of bromocriptine were less evident. The antitumoral effects of bromocriptine on prolactin-secreting adenomas is independent and additional to the effects of pituitary radiotherapy or microsurgery, and has therapeuticical implications.

Acromegaly↗
PubMedDate not supplied

Hormonal evidence for the dissemination through the cerebrospinal fluid, of secreting cells from invasive pituitary adenomas.

In 13 patients with invasive pituitary adenomas submitted to pituitary surgery (5 HGH-secreting adenomas, 6 prolactin-secreting adenomas, 2 non-secreting adenomas), the concentrations of HGH and prolactin (PRL) constantly decreased after operation both in the cerebrospinal fluid (CSF) and serum, and the CSF/serum ratio remained under one, with few exceptions. These last cases (2 with acromegaly, 2 with invasive prolactinomas), showed an increase of HGH or PRL concentrations in CSF when serum levels decreased; the CSF/serum ratio rose above one within 2 weeks post surgery in 2 patients, and within 2 years post surgery in another two. The circulation of CSF was not obstructed. This indicated the appearance of a new, extrapituitary source for secreting HGH or PRL directly into the CSF, a source which most probably developed through the dissemination, via CSF, of secreting cells from malignant pituitary adenomas.

Acromegaly↗