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Biomedical subjects

D Rabin

Publications and source records attributed to D Rabin.

At least 55 records · Page 3Linked to original sources
PubMed1982

Familial insensitivity of the pituitary and periphery to thyroid hormone: a case report in two generations and a review of the literature.

A clinically euthyroid 2-yr-old girl was found to have diffuse goiter that measured 3 X 5.5 cm with a prominent systolic bruit. Serum free T4 (3.4 ng/dl) and serum T3 (360 ng/dl) remained elevated for the next 10 months even though she remained clinically euthyroid. Elevation of serum free T4 (3.0 ng/dl) and serum T3 (265 ng/dl) was also present in the 24-yr-old nongoitrous mother who had symptoms and signs of hypothyroidism. Following intravenous injection of TRH, basal TSH levels of 2.7 and 2.8 microunits/ml increased to peak values of 17 and 21 microunits/ml at 30 min in the daughter and mother, respectively. Administration of exogenous T3 followed by sequential testing with boluses of TRH revealed retention of TSH responsiveness in both daughter and mother during pretreatment with dosage regimens of T3 below 125 micrograms daily. Maintenance of TSH responsiveness to TRH in the presence of elevated levels of serum free T4 and serum T3 indicates relative pituitary insensitivity to thyroid hormone which could be overridden by increasing the circulating levels of serum T3 three to fivefold over the already elevated basal levels. The absence of clinical signs of thyrotoxicosis indicates peripheral insensitivity to thyroid hormone with elevated circulating concentrations presumptively compensating for the defect. Resistance to thyroid hormone in two generations of the same family suggests genetic inheritance, and is concordant with four earlier reports of familial aggregation in this syndrome.

Adult↗
PubMed1982

Dissociation of LH and FSH Responses to LHRH during estrogen therapy of patients with ovarian failure.

This study examines the effect of oral estrogen treatment on gonadotropin secretion in three young women with gonadal failure. Each subject was treated with 0.1 mg BID of ethinyl estradiol for four weeks, and the LH and FSH responses to 200 microgram of intravenously administered LHRH were measured basally and weekly during therapy. Significant reduction of basal levels of FSH occurred within one week of treatment, with obliteration of LHRH-mediated FSH responsiveness within two weeks. By contrast, basal levels of LH were significantly reduced by the end of the second week of treatment, and LHRH-mediated LH levels were sustained for three weeks. In one subject an LHRH test was performed every other day for two weeks after cessation of therapy. Return of FSH responsiveness was delayed one week beyond that of LH, which occurred within three days of discontinuation of estrogen. These results indicate that during the early phase of oral estrogen replacement therapy, FSH secretion may be selectively blunted; after discontinuation of treatment, recovery of FSH secretion lags behind recovery of LH.

Adult↗
PubMed1982

Comparable testosterone responses are produced by constant infusion of LH or GnRH in normal men.

Luteinizing hormone (LH) was infused continuously at a rate of 1.3 IU/min to 4 normal adult men. A 4 to 5-fold increase in serum LH was noted by 8 hours. Serum FSH declined steadily throughout the infusion period in the face of rising concentrations of gonadal steroids. Basal plasma testosterone of 4.7 +/- 0.4 ng/ml rose progressively to a peak of 11.1 +/- 0.9 ng/ml at hour 56 (p less than 0.005). A similar pattern was demonstrated by plasma androstenedione. Plasma 17 alpha-hydroxyprogesterone rose from a basal concentration of 0.81 +/- 0.14 ng/ml to a peak concentration of 2.6 +/- 0.3 ng/ml at hour 36 of the infusion and subsequently declined. A similar course was followed by serum estradiol-17 beta, which achieved a maximal concentration of 70.0 +/- 10.4 pg/ml at hour 36. Results are compared to those obtained with continuous infusion of GnRH in normal adult men. Testosterone responses were similar, whereas elevations in 17 alpha-hydroxyprogesterone and estradiol were higher following GnRH infusion. This difference may be consequent upon a direct gonadal effect of GnRH, or may be secondary to local regulation of testicular steroidogenesis by estradiol-17 beta.

Adult↗
PubMed1982

Absorption and disposition of a glucose load in the conscious dog.

The quantitative disposition of an intragastrically administered glucose load was studied in eight conscious 18-h fasted dogs using isotopic and arteriovenous (A-V) techniques. During the control period, the gut utilized 25% of the basal net hepatic glucose output (2.8 +/- 0.2 mg.kg-1.min-1). After glucose ingestion, 80% of the load was absorbed as glucose, 11% was converted across the gut to lactate and alanine, and 4% was oxidized to CO2. Two percent of the load remained in the gut 4 h after glucose administration and 3% was unaccounted for. During the absorptive period, net hepatic glucose balance (NHGB) varied considerably (mean range = output of 1.8 to uptake of 9.1 mg.kg-1.min-1), while endogenous hepatic glucose production (Ra hp) showed a consistent 80% suppression. The total net hepatic glucose uptake during the absorptive period (150 +/- 10 min) accounted for the disposal of 24 +/- 10% of the ingested load, and the amount of glucose escaping the splanchnic bed was 40 +/- 3%. Overall NHGB correlated positively with basal arterial glucose and insulin levels and negatively with basal arterial glycerol and FFA and with peak absorptive arterial glucose and insulin levels. These data suggest that the hepatic response to an ingested glucose load depends in part on the degree of metabolic fast of the animal at the time of glucose ingestion; the latter may be a major determinant of the roles played by the tissues in glucose disposal.

Absorption↗
PubMed1982

Intermittent long-term administration of a potent gonadotropin-releasing hormone agonist in normal men.

The effects on pituitary-gonadal function of the potent gonadotropin-releasing hormone agonist D-trp6-pro9-n-ethylamide-LHRH (LRFA), 50 micrograms subcutaneously every 4th day for 10 weeks, were evaluated in seven normal men. A modest rise in mean serum LH levels was noted during the treatment period. Mean serum FSH levels were unchanged. Mean plasma testosterone (T) levels remained at 3.1 ng/ml or above. Sperm density during the control period varied widely within and between subjects, with a mean range of 69-137 million/ml. The mean sperm density fell to a nadir of 40 million/ml during treatment, but no consistent pattern was observed for each subject, with values varying between 4 and 368 million/ml. Elevated LH and T values were observed on eight and seven occasions, respectively, in five subjects, and corresponded to blood samples drawn 24 and 48 h after the last LRFA injection. Depressed T values were observed on 10 occasions in six patients, and in all but one, corresponded to blood drawn 72 and 96 h after the last injection. One subject had daily blood samples drawn at the start of and 4 weeks after beginning therapy. An agonist effect on LH, FSH, T, and estradiol was observed both times, although the effect was blunted on the second occasion. We conclude that treatment every 4 day with LRFA does not appear to be a promising regimen to induce consistent suppression of the pituitary-gonadal axis in man.

Adult↗
PubMed1982

Isolated ACTH deficiency: a heterogeneous disorder. Critical review and report of four new cases.

Isolated adrenocorticotropin (ACTH) deficiency is a rare cause of secondary adrenocortical insufficiency. This review summarizes the clinical and laboratory features of 39 previously reported cases plus 4 new patients. The clinical manifestations of isolated ACTH deficiency are variable, nonspecific and similar to those seen in adrenocortical insufficiency of any cause. The diagnosis of isolated ACTH deficiency due to intrinsic pituitary disease is made unequivocally when all the following criteria are met: 1) low basal urinary 17-hydroxycorticosteroid (17-OHCS) levels with or without low basal plasma cortisol, 2) low or normal basal plasma ACTH, 3) stimulation of cortisol, 17-OHCS or both during prolonged ACTH administration, 4) lack of 17-OHCS elevation in response to metyrapone and 5) normal secretory indices of other pituitary hormones. Isolated ACTH deficiency secondary to suprapituitary (e.g., hypothalamic) dysfunction is also based upon the above criteria, but, in addition, is associated with stimulation of cortisol and ACTH secretion following vasopressin administration.

17-Hydroxycorticosteroids↗
PubMed1981

Reversible inhibition of testicular steroidogenesis and spermatogenesis by a potent gonadotropin-releasing hormone agonist in normal men: an approach toward the development of a male contraceptive.

We studied the antifertility effects of a potent gonadotropin-releasing hormone agonist, D-Trp6-Pro9-N-ethylamide-LHRH (LHRHA) in eight normal men, who received daily subcutaneous injections for six to 10 weeks. Plasma testosterone levels fell substantially in all eight. Plasma 17-hydroxyprogesterone and serum estradiol-17 beta levels decreased concordantly with plasma testosterone. Impotence developed in five men between the sixth and seventh weeks of treatment, with resolution in each case within two weeks of stopping treatment. Serum gonadotropin levels also fell during treatment, briefly rebounding above basal levels when therapy ended. Sperm density and motility fell t a nadir during the seventh to 18th week after therapy. In six subjects sperm levels fell to 6 X 10(6) sperm per milliliter or less, and in the other two they decreased 70 and 86 per cent below basal mean values. Sperm density returned to pretreatment levels in all men during the 10-to-14-week recovery period. These results are consistent with LHRHA-induced pituitary "desensitization" but do not exclude a direct inhibitory effect of LHRHA on testicular steroidogenesis and spermatogenesis.

Adult↗
PubMed1981

A familial glucagonoma syndrome: genetic, clinical and biochemical features.

A family with multiple endocrine neoplasia type I (MEN-I) is described in which three members had A-cell pancreatic tumors. Two of these members had classic glucagonoma syndromes. The proband, a 62 year old woman, had a high (less than or equal to 9.2 ng/ml) basal plasma glucagon level, most of which eluted in the 3,500 dalton fraction. Plasma glucagon increased following the ingestion of mixed meals and arginine. Secretin, which, in the dog, has been reported to inhibit normal glucagon secretion, provoked a twofold increase in 3,500 dalton plasma glucagon concentration. Increased plasma glucagon in the proband was associated with mild hyperglycemia and insulin resistance. Somatostatin infusion suppressed peripheral glucagon and insulin levels, and increased blood glucose levels. The unique responses to secretin and somatostatin observed in this patient may be diagnostically important in syndromes of inappropriate or autonomous glucagon secretion.

Adenoma, Islet Cell↗
PubMed1981

Retardant effect of hyperglycemia on the rise in plasma fatty acids following insulin withdrawal in man.

The present study was undertaken to examine the influence of hyperglycemia in retarding the rise in circulating FFA noted after acute insulin withdrawal in man. The arterial FFA response to somatostatin administration was measured in the presence of (a) euglycemia and (b) hyperglycemia. In seven normal men who received somatostatin (0.9 mg/h) with euglycemia maintained by exogenous glucose infusion plasma insulin levels fell to levels 4 uU/ml and plasma FFA concentrations rose from 659 +/- 123 to 2057 +/- 268 uEq/l. When somatostatin was infused with hyperglycemia maintained at approximately 230 mg/dl, plasma insulin levels were again maintained at levels 4 uU/ml. Despite similar insulinopenia plasma FFA concentrations rose from 510 +/- 56 to only 1125 +/- 180 uEq/l, significantly less than in the previous protocol (p less than 0.01). These data indicate that hyperglycemia per se significantly attenuates the rise in circulating FFA caused by acute insulin withdrawal in man.

Adolescent↗
PubMed1981

Amino acid disposition by liver and gastrointestinal tract after protein and glucose ingestion.

Hepatic uptake and gut and splanchnic output of amino acids were determined after administration of protein and glucose loads in conscious dogs with indwelling catheters in the femoral artery and portal and hepatic veins. Oral or parenteral glucose given with a beef meal blunted the rise in arterial amino acids relative to that seen with ingestion of beef alone. Gut amino acid output was considerably delayed with oral hypertonic glucose, but was unchanged with parenteral glucose and with oral isotonic glucose. Ingestion of beef with oral hypertonic mannitol, a nonabsorbable sugar alcohol, delayed the rise in gut amino acid output in a manner similar to that seen with beef plus oral hypertonic glucose. We have evaluated the relationship between circulating amino acids, circulating hormone concentrations, and amino acid metabolism. Significant correlations with hepatic amino acid uptake were found for insulin, for arterial and portal amino acid levels, and for gut amino acid output. Partial correlation analysis suggests that gut amino acid output is the major determinant of hepatic amino acid uptake.

Amino Acids↗
PubMed1981

Characterization of human anti-luteinizing hormone-releasing hormone (LRH) antibodies in the serum of a patient with isolated gonadotropin deficiency treated with synthetic LRH.

In this report we describe the characteristics of human anti-LRH antibodies detected in the serum of a male patient with isolated gonadotropin deficiency. He had received 90 days of therapy with LRH (1 mg, sc, three times daily) and was then placed on three cycles of intermittent therapy (3 weeks of LRH daily, followed by hCG every 3 days for 15 days). At the start of the fourth cycle of therapy with LRH, he developed urticaria at the site of injection, at sites of previous LRH injections, and at distant sites. Upon direct skin testing, the patient reacted positively to 0.02 ng LRH intradermally. A positive intradermal reaction was induced in a normal adult male by preparing his skin with 0.1 ml of the patient's serum and, 24 h later, injecting 0.2 microgram LRH at that site. A binding factor for LRH was detected in the patient's serum by incubation with [125I]LRH. The serum bound 33% of tracer compared to 6% in control serum. We have detected both immunoglobulin G and immunoglobulin E antibodies against LRH in the patient's serum. We have compared displacement of tracer by synthetic LRH with displacement achieved by a series of analogs. Displacements of tracer by LRH, [Lys8]LRH, [D-Trp6,Pro9-NEt]LRH, [des-Gly10]LRH, and [Phe2]LRH were similar, whereas the potencies of Ac-LRH5-10 and AcLRH2-10 were 0.1% or less.

Adult↗
PubMed1981

Characterization of steroid production in cultured human choriocarcinoma cells.

Progesterone is the major steroid synthesized by the JEG-3, BeWo, and JAR cell lines of choriocarcinoma. A lesser amount of pregnenolone is produced. The 17alpha-hydroxy derivatives of these steroids are only minimally present in three lines. The addition of fetal calf serum to the culture medium modestly increases the synthesis of these steroids, but increases the quantity of 17beta-estradiol produced by 30- to 90-fold. The addition of dehydroepiandrosterone, dehydroepiandrosterone sulfate, androstenedione, androstenediol, and testosterone was shown to stimulate 17beta-estradiol synthesis. There is a clear dose-response relationship between the amount of testosterone added and the quantity of 17beta-estradiol produced. These results indicate that 3beta-hydroxysteroid dehydrogenase-isomerase, 17beta-ol dehydrogenase, and aromatase are active in cultured choriocarcinoma cells, whereas 17beta-hydroxylase and 17-20 desmolase do not appear to be functional in these cells. It is concluded that the stereoidogenic capabilities of choriocarcinoma cells in culture are similar to those of the in vivo placenta and support their use as an experimental model of placental steroidogenesis.

Adrenal Hyperplasia, Congenital↗
PubMed1981

Long term therapy with luteinizing hormone-releasing hormone in isolated gonadotropin deficiency: failure of therapeutic response.

We have evaluated the therapeutic response to exogenous LRH (1 mg, sc, either twice daily or three times daily) in six subjects with isolated gonadotropin deficiency. Four males were treated for 6 months, of whom two showed a transient rise in serum testosterone. However, testosterone levels subsequently remained at pretreatment levels in each of the four subjects during LRH therapy. One of the two female subjects displayed a transient rise in 17 beta-estradiol levels. All four males showed a notable rise in testosterone after hCG, and the one female tested responded to menotropins, while receiving LRH. We propose that the number of quanta of gonadotropins released per day with our therapeutic regimen was inadequate to generate a normal gonadal response.

Adult↗
PubMed1981

Genetic and endocrine findings in a 31-year-old 45,X/46,Xdel(Y)(q12) male.

This report describes genetic, endocrine, and histological findings in a 31-yr-old 45,X/46,Xdel(Y)(q12) male with gynecomastia and azoospermia. A preponderance of 45,X cells was found in all tissues studied. Endocrine data suggested an abnormal Leydig cell-pituitary gonadotroph axis, although the basal testosterone level and the response to short term administration of hCG were normal. Testicular histology showed Leydig cell hyperplasia and seminiferous tubule atrophy. These findings are compared to 17 similar cases in the literature. A characteristic of all these cases is a morphologically abnormal Y-chromosome, which probably results in the 45,X cell line. The masculinizing genes on the remaining Y-chromosomes are functionally intact and promote a male phenotype in infancy and adolescence. Azoospermia is usually present, and gynecomastia or hypogonadism occurs later in life. Comparison with other nonmasculinized 45,X/46,XY cases supports existing theories regarding the function of the various segments of the Y-chromosome.

Adult↗
PubMed1981

Isolated growth hormone deficiency, ovarian dysgenesis and Turner stigmata with normal chromosomal complement.

An 18 year old white female presented with short stature and amenorrhoea. Her height was 135 cm, weight 46.6 kg; she had a broad neck, a high arched palate, short fifth metacarpals bilaterally, short third, fourth and fifth metatarsals bilaterally and minimal breast development. Although the clinical picture strongly suggested Turner's syndrome, investigations revealed: (a) normal female 46,XX chromosomal pattern on analyses of skin, lymphocytes and ovarian tissue; (b) undetectable serum growth hormone levels; (c) pre-pubertal oestradiol-17 beta levels; (d) only very occasional primordial follicles on ovarian biopsy with a thickened capsule; and (e) basal LH and FSH levels of 6.8 to 9.6 mIU/ml which rose after LRH injection to 90 and 26 mIU/ml, respectively. The patient has the unusual combination of growth hormone deficiency, gonadal dysgenesis and Turner stigmata with a normal chromosomal complement.

Adolescent↗
PubMed1981

Autonomous hyperprolactinemia in tuberous sclerosis.

Amenorrhea and galactorrhea developed in a female patient with tuberous sclerosis. There was no evidence of a pituitary tumor; she had an abnormal EEG, and computed tomographic scan showed multiple intracerebral calcifications but no lesions in the pituitary gland or hypothalamus. She had fixed hyperprolactinemia that was unresponsive to protirelin, chlorpromazine, levodopa, bromocriptine mesylate, or estrogen. The circulating prolactin may be of pituitary origin or may possibly be secreted ectopically by a hamartoma.

Adolescent↗