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Biomedical subjects

Z Laron

Publications and source records attributed to Z Laron.

At least 163 records · Page 9Linked to original sources
PubMed1988

Effect of acute administration of insulin-like growth factor I in patients with Laron-type dwarfism.

Biosynthetic insulin-type growth factor I (IGF-I) was given as an intravenous bolus of 75 micrograms/kg to 9 patients with Laron-type dwarfism. Rapid onset of hypoglycaemia (-45% of basal level) was associated with a reduction in plasma insulin (-55% of basal level); thus, the lack of growth hormone receptors in this condition does not apply to IGF-I receptors and post-receptor pathways. Long-term treatment may therefore be beneficial in Laron-type dwarfism.

Adult↗
PubMed1988

When should hydrocortisone therapy be instituted in children with hypopituitarism?

The records of 72 pediatric and adolescent patients with multiple hypothalamic and/or pituitary hormone deficiencies of nontumoral origin who were followed up for years and receiving somatotropin, thyroxine, and sex hormones at the appropriate age have been reviewed. According to their corticotropin-releasing factor-corticotropin-cortisol (CAC) axis function as evaluated by basal plasma cortisol levels and the response of cortisol to insulin hypoglycemia and to corticotropin-releasing factor, the patients were divided into three groups: group 1 (n = 25), patients with multiple hypothalamic and/or pituitary hormone deficiencies with normal CAC axis; group 2 (n = 38), patients with partial CAC deficiency without cortisol replacement therapy (hydrocortisone); and group 3 (n = 9), patients with CAC deficiency receiving hydrocortisone therapy (5 to 10 mg/d). Repeated CAC axis evaluation in patients of group 2 over years revealed a progressive decrease in the basal and stimulated cortisol levels with age and pubertal advancement. Despite the low cortisol levels and the low cortisol response to insulin hypoglycemia, these patients did not have clinical symptoms until the end of puberty when nine of 24 patients complained of abdominal pain, weakness, or anorexia. Linear growth, which was followed up in all patients at regular intervals, showed a lower growth velocity and irregular growth in response to somatotropin treatment in the patients receiving low doses of hydrocortisone (group 3 patients when compared with group 2 patients not receiving hydrocortisone).

Adolescent↗
PubMed1988

Comparison of dental findings in patients with isolated growth hormone deficiency treated with human growth hormone (hGH) and in untreated patients with Laron-type dwarfism.

The effect of human growth hormone (hGH) on dental structures was investigated by comparing two groups of patients with hypopituitarism. One group of 19 patients with isolated growth hormone deficiency who received hGH replacement therapy was compared with a group of 13 patients with high immunoreactive growth hormone and IGF-I deficiency, Laron-type dwarfism, who could not benefit from hGH treatment. Plaster casts of the dentitions and panoramic radiographs were obtained from all patients and analyzed for dental age, arch length, arch circumference, and width of teeth. the main findings were that (1) hGH therapy did not accelerate dental age but enhanced bone age; (2) the mandible was significantly smaller in the untreated group but no significant difference was found between the groups in the maxilla; (3) third molars were missing in more than 90% of the patients with Laron-type dwarfism whereas hypodontia of other teeth was found in 30% of all the patients; and (4) crowding was less prevalent than expected and the mesiodistal width of the teeth seemed to be smaller.

Adolescent↗
PubMed1988

Plasma cortisol, prolactin, growth hormone, and immunoreactive beta-endorphin response to fenfluramine challenge in depressed patients.

The effect of a single dose (60 mg p.o.) of the serotonin agonistic agent fenfluramine (FNF) on plasma cortisol, prolactin (PRL), growth hormone (GH), and immunoreactive beta-endorphin (ir-beta-EP) levels was assessed in eight major depressed patients and eight controls. The hormones were monitored at basal level (0') and hourly during 5 h following FNF administration. The pharmacological challenge caused an elevation of 80% in PRL secretion in the healthy controls and only 42% in the depressed patients. However, the actual prolactin response (delta max) failed to discriminate depressed patients from controls. A blunted response followed by a decrease (33%) in serum cortisol levels was observed in depressed patients 5 h after drug administration while an increase of 94% was obtained in controls after 3 h. FNF provocation did not affect GH and ir-beta-EP plasma levels. The blunted cortisol responsiveness to FNF administration in depressed patients may reflect functional hypoactivity of central serotonergic system at least during the acute phase of major depression. It is not clear why the cortisol hyporesponsivity in depressed patients is not accompanied by a similar reduced PRL response to FNF challenge.

Adult↗
PubMed1988

Changes in endogenous insulin secretion during childhood as expressed by plasma and urinary C-peptide.

Basal fasting values of plasma C-peptide (CP), plasma insulin and 24 h urine CP were determined in 224 normal non-obese subjects of both sexes ranging in age from 1 to 20 years. Analysis of the results by age, pubertal rating, sex and bone age (BA) during childhood showed that mean +/- SD plasma CP levels in both sexes rose from 0.07 +/- 0.08 pmol/ml at the age of 1-2 years to 0.21 +/- 0.11 pmol/ml at 8-10 years. Mean +/- SD plasma insulin levels in both sexes rose from 3.2 +/- 4.3 microU/ml at the age of 1-2 years to 5.9 +/- 4.5 microU/ml at 8-10 years. Mean +/- SD urine CP levels rose from 6.5 +/- 2.8 pmol/mg creatinine per 24 h at the age of 2-8 years to 7.7 +/- 3.5 pmol/mg creatinine per 24 h at 8-11 years in both sexes. During puberty, plasma and urine CP and plasma insulin levels rose further to peak at pubertal stage P3, the values in females being higher (CP = 0.32 +/- 0.06 pmol/ml) than those in males (CP = 0.22 +/- 0.06 pmol/ml) (P less than 0.005). Plasma insulin levels in females were 13.2 +/- 6.9 microU/ml and 6.4 +/- 3.1 microU/ml in males (P less than 0.05). Urine CP levels were 14.5 +/- 5.7 pmol/mg creatinine per 24 h and 10.8 +/- 5.4 pmol/mg creatinine per 24 h in females and males respectively (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

A comparison of IGF-I levels measured by two commercially available radioimmunoassays.

Insulin-like growth factor I levels were measured in a parallel fashion in 77 extracted sera using the INCSTAR RIA (radioimmunoassay) and in the EDTA plasma of the same subjects by the NICHOLS RIA. The subjects suffered from untreated hGH deficiency, short stature, delayed and precocious puberty and acromegaly. Significant differences (P less than 0.05) were found between the mean IGF-I levels of all groups using both RIA systems. However, using the INCSTAR RIA, 85% of IGF-I values in untreated hGH deficiency were below normal, and a rise in IGF-I detected in the sera of all 5 patients who were treated with hGH. Using NICHOLS RIA, 55% of basal IGF-I values were below normal and a hGH-stimulated rise in IGF-I was found in only two of the treated patients. The INCSTAR RIA seems more precise and reproducible than the NICHOLS RIA and enables better discrimination of hGH-deficient patients from age-matched controls.

Acromegaly↗
PubMed1988

Endocrinological parameters and cell-mediated immunity postoperation for cryptorchidism.

Andrological and endocrinological parameters and cell-mediated immunity (CMI) were assessed in 25 postpubertal males who had undergone repair of unilateral or bilateral cryptorchidism in childhood or early adolescence. Among 20 patients with unilateral cryptorchidism, approximately 30% had decreased sperm density, whereas among 5 bilaterally affected, 1 was azoospermic and 2 oligozoospermic. In most patients the motility and viability values were normal, although the percentage of morphologically pathological sperm was higher than normal. Levels of testosterone, dihydrotestosterone, LH, and prolactin were within normal ranges in all the patients. Levels of FSH were slightly elevated. These findings may suggest a better fertility prognosis of postcryptorchid oligozoospermic patients than in patients with oligozoospermia of other etiology. CMI toward autologous semen revealed a positive reaction in 80% of the bilateral group and in 45% of the unilateral group. This response might be due to the damage of seminiferous tubules of undescended testis causing unmasking and exposure of antigenic determinants.

Adolescent↗
PubMed1988

Growth hormone (hGH) secretion and turnover in three patients with Laron-type dwarfism.

The 24-h secretory pattern of hGH was studied by the aid of a continuous blood withdrawal pump in three Laron-type dwarfism (LTD) patients and compared with that in sex- and age-matched normal control subjects. It was found that the secretion of hGH was enhanced in the LTD patients, but in all three the diurnal secretory profile, as expressed by the number of pulses and the sleep-related maximal pulse, was preserved. In the younger LTD patients, women aged 19 and 21 years, the number of pulses was 9 and 7 (compared with 6 in the control subjects), the maximal hGH pulse amplitude was 164 and 280 ng/ml (compared with 135 ng/ml), the area under the curve (AUC) was 560 and 780 (compared with 268), and the average integrated concentration (A-IC) of hGH was 33.9 and 23.4 ng/ml (compared with 11.3). In the older LTD patient, a man aged 27 years, the hGH secretion was lower than that in the LTD women, but still higher than that in normal matched controls: the number of pulses was 4 (control 2), maximal pulse amplitude 67 ng/ml (control 19), AUC 231 (control 51), and A-IC 9.9 ng/ml (control 2.2). The decline in hGH secretion, which is characteristic of advancing age in normal subjects, seems to occur in LTD as well. Metabolic clearance rate (MCR) and production rate (PR) of hGH were measured in the 19-year-old female LTD patient. Her MCR was 73.4 ml/m2 per min, and her PR was 2,480 ng/ml compared with 158.3 and 839, respectively, in a normal subject. The exaggerated PR explains the elevation of plasma hGH in this syndrome and is probably the result of a lack of negative feedback due to insulin-like growth factor deficiency.

Adolescent↗
PubMed1987

Effects of acute and chronic methylphenidate administration on beta-endorphin, growth hormone, prolactin and cortisol in children with attention deficit disorder and hyperactivity.

The effect of 5 mg/p.o. methylphenidate (MPH) challenge on beta-endorphin (beta-EP), growth hormone (GH), prolactin (Prl) and cortisol was investigated in 16 children suffering from attention deficit disorder with hyperactivity (ADDH) before and after 4 weeks MPH treatment. The study population consisted of 13 males and 3 females aged 6-11 years. All patients were drug free for at least 3 months prior to investigation. The severity of ADDH symptomatology and response to MPH chronic treatment was assessed using parent/teacher abbreviated Conners rating scale. Blood samples for beta-EP, cortisol, Prl and GH were drawn before initiation of treatment (basal pre-treatment level), 2 hours after MPH challenge, 4 weeks after MPH treatment (basal post-treatment level) and 2 hours after re-challenge with MPH. Chronic MPH treatment resulted in a decrease in basal Prl levels (5.5 +/- 2.8 vs 3.7 +/- 1.9 ng/ml; p less than 0.05). Pre-treatment challenge stimulates significantly both beta-EP (15.0 +/- 7.5 vs 12.5 +/- 5.3 pmol/l; p less than 0.05) and cortisol secretion (20.6 +/- 6.6 vs 12.6 +/- 5.8 micrograms/dl; p less than 0.05), and suppressed Prl secretion (4.0 +/- 1.5 vs 5.5 +/- 2.8 ng/ml; p less than 0.05). Re-challenge with MPH enhanced beta-EP levels (14.9 +/- 8.6 vs 10.6 +/- 5.0 pmol/l; p less than 0.05) but failed to affect cortisol, Prl and GH secretion. The acute and chronic neuroendocrine effects of MPH administration might be related to its dopaminergic and adrenergic agonistic activity. It might be that the stimulatory effect of single and repeated acute MPH administration on beta-EP release contributes to the beneficial effect of MPH treatment in ADDH children.

Attention Deficit Disorder with Hyperactivity↗
PubMed1987

Cardiorespiratory depression and plasma beta-endorphin levels in low-birth-weight infants during the first day of life.

Twenty-nine premature infants were studied to determine whether neonatal asphyxia, apnea, and low blood pressure in the first day of life are associated with elevated plasma beta-endorphin concentrations. Plasma beta-endorphin levels were determined at 0.5 to 2, 4 to 6, and 18 to 24 hours of life, using radioimmunoassay. Premature infants with moderate or severe asphyxia (n = 19) had higher levels at 0.5 to 2 hours of age (32.1 +/- 6.7 vs 16.4 +/- 7.4 pmol/L) and significantly higher levels at 4 to 6 hours of age (50.4 +/- 10.0 vs 22.9 +/- 9.2 pmol/L) compared with the ten nonasphyxiated premature infants. A significant elevation in levels at age 0.5 to 2 hours (39.4 +/- 9.9 vs 17.7 +/- 4.4 pmol/L) and age 4 to 6 hours (59.3 +/- 13.8 vs 27.1 +/- 17.1 pmol/L) was observed in premature infants with low blood pressure or impaired perfusion (n = 12) who required the administration of volume expanders. No differences were observed in premature infants with and without apnea. It may be speculated that the increased endogenous release of beta-endorphins in response to perinatal asphyxia may play a role in the pathogenesis of shock observed in the first day of life.

Apnea↗
PubMed1987

The effect of acute and repeated electroconvulsive treatment on plasma beta-endorphin, growth hormone, prolactin and cortisol secretion in depressed patients.

The effects of single and repeated electroconvulsive treatment (ECT) on beta-endorphin (beta-EP), cortisol, growth hormone (GH) and prolactin (Prl) plasma levels were investigated in nine depressed patients. Blood samples were monitored a day before ECT, the day of the first and sixth ECT (0, 30, 60 and 90 min after seizures), the day afterwards and 4 weeks after termination of the ECT course. A significant elevation of beta-EP levels was achieved immediately with and 24 h after the first and the sixth ECT. A transient increase in basal beta-EP was observed 1 day following the sixth ECT in comparison with pre-treatment level. Peak and 30 min levels of cortisol were increased compared with baseline by the first ECT. The former (peak) but not the latter (30 min) were increased also at the sixth treatment. GH levels were decreased the day after the first ECT in comparison with the pre-treatment levels and immediately following each ECT in comparison with baseline. A trend toward elevation of Prl was observed immediately after the first and sixth ECT, although the rise did not reach significant levels. ECT administration stimulated beta-EP and cortisol secretion and suppressed human GH release, possibly by activation of endorphinergic and/or serotonergic systems. These mechanisms might be involved in the beneficial effect of ECT in depression.

Adult↗
PubMed1987

Episodic hormone secretion during sleep in Kleine-Levin syndrome: evidence for hypothalamic dysfunction.

"Acute" hypothalamic-pituitary function tests including insulin tolerance test, LRH, ACTH and TRH stimulation tests and nocturnal secretory pattern of human growth hormone, 11-OHCS, prolactin, FSH, LH and TSH were studied in a 23-year-old male with Kleine-Levin syndrome during the course of a typical hypersomnic attack. The "acute" tests revealed paradoxical growth-hormone response to TRH stimulation, borderline high basal plasma prolactin levels with normal response to TRH. The hormonal secretory pattern during sleep revealed abnormalities in LH, 11-OHCS and prolactin secretion. These together with the results of the "acute" tests are indicative of an abnormality in the hypothalamic regulation of various pituitary hormones. This observation may indeed be the first laboratory demonstration confirming a long-standing hypothesis that Kleine-Levin syndrome is related to hypothalamic dysfunction.

Adult↗