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At least 127 records · Page 7Linked to original sources
PubMed1988

Evidence for an adrenal contribution to plasma digitalis-like factors.

Digitalis-like factors (DLF) were assayed on plasma collected serially using antibody to digoxin: (1) after intravenous ACTH (n = 3 patients) and (2) after 0.15 U/kg crystalline insulin, 50 micrograms gonadotropin-releasing hormone and 0.2 mg thyrotropin-releasing hormone (n = 7) as a combined pituitary function test. Patients had either hypothalamic-pituitary or ovarian problems. Mean values for DLF rose fourfold after ACTH, and by a factor of 2.3 with the combined pituitary function test. DLF rose at least 50% in all 10 subjects. In 3 dogs, adrenal vein values for DLF were on average more than double values in either adrenal artery or lower vena cava. These results suggest that certain DLFs have an adrenal origin.

Adrenal Glands↗
PubMedDate not supplied

Transsphenoidal hypophysectomy in beagle dogs: evaluation of a microsurgical technique.

OBJECTIVE: Assessment of a microsurgical technique for transsphenoidal hypophysectomy in dogs. STUDY DESIGN: Prospective study using physical examination, pituitary function testing, computed tomography (CT), and histological examination at autopsy. ANIMALS OR SAMPLE POPULATION: Eight laboratory beagle dogs. METHODS: Pituitary function was assessed before and at 10 weeks after hypophysectomy by combined administration of four releasing hormones (anterior pituitary), administration of haloperidol (pars intermedia), and infusion of hypertonic saline (posterior pituitary). RESULTS: CT imaging enabled accurate preoperative localization of the pituitary. Appropriate positioning and surgical technique facilitated exposure of the pituitary and its extraction without hemorrhage. Postoperative recovery was generally uncomplicated. None of the eight dogs had somatotropic, gonadotropic, lactotropic, melanotropic, or posterior pituitary responses to stimulation at 10 weeks after hypophysectomy. Four dogs (ACTH nonresponders) also had no corticotropic response and four (ACTH responders) had small but significant responses in the combined anterior pituitary function test. Adrenocortical atrophy was more pronounced in the ACTH nonresponders than in the responders. No residual pituitary tissue was found along the ventral hypothalamic diencephalon but nests of pituitary cells were found embedded in fibrous tissue in the sella turcica. CONCLUSIONS: The surgical technique proved to be safe and effective. Microscopic nests of pituitary cells in the sella turcica may be responsible for residual corticotropic response to hypophysiotropic stimulation after hypophysectomy. CLINICAL RELEVANCE: The surgical technique may be used in the treatment of dogs with pituitary-dependent hyperadrenocorticism. The corticotropic response is the most sensitive criterion in assessing completeness of hypophysectomy in dogs.

Adrenocortical Hyperfunction↗
PubMed1973

Combined test for assessment of anterior pituitary function.

A combined test consisting of the simultaneous administration of insulin, thyrotrophin-releasing hormone (TRH), and luteinizing hormone and follicle stimulating hormone-releasing hormone (LH/FSH-RH) was performed in 24 people. Eleven of these also had the three individual tests performed separately, and the remaining 13 had a separate test of either LH/FSH-RH and TRH together or singly at a later date. In both normal people and patients, whether the tests were performed alone or in combination, no difference was found between the hormone responses (growth hormone, cortisol, LH, FSH, thyroid-stimulating hormone) seen to these stimuli.It is proposed that combined administration of insulin and the hypothalamic releasing hormones may be used as a single test for the assessment of anterior pituitary function. The test is convenient and time saving, and with care can be performed in outpatients.

Blood Glucose↗
PubMed1997

Atherosclerosis, aortic stenosis and sudden onset central diabetes insipidus.

The majority of cases of central diabetes insipidus are still pathogenetically unclear (idiopathic). Atherosclerotic cholesterol emboli might be partly responsible for some of these idiopathic cases. A 54-year-old woman with known aortic valve stenosis and a history of a transitory ischemic attack presented with sudden-onset polyuria and polydipsia of up to eight l/d, which had started acutely with headaches. She had been treated with lithium for 3 years because of cyclothymic depression. Plasma sodium was in the upper normal range (142-148 mmol/l). Hypertonic saline infusion during lithium therapy revealed a normal threshold of thirst and resetting of vasopressin secretion (osmotic threshold > 300 mosmol/l), whereas vasopressin reserve was normal. Lithium withdrawal led to an even greater delay of vasopressin release upon hypertonic saline infusion (> 310 mosmol/l). Pituitary function tests revealed a normal anterior pituitary function. MR imaging of the hypothalamo-hypophyseal region showed a normal hypothalamic region and a highly intensive neurohypophyseal signal in the T1-weighted image. The patient responded well to desmopressin. We suggest that in this rare case clinical symptoms as well as biochemical findings like impairment of AVP release might be related to a minor structural hypothalamic damage by a vascular lesion, caused, for example, by an atheromatous (cholesterol) embolism in the hypothalamic region responsible for integration of osmoreceptor function and AVP-secretion. The patient's atherosclerosis and aortic stenosis might be responsible for this event.

Aortic Valve Stenosis↗
PubMed1987

Investigation of anterior pituitary function in elderly in-patients over the age of 75.

Dynamic pituitary function tests were carried out on 50 randomly selected in-patients, (30 women and 20 men) over the age of 75 during early convalescence. Twenty-five subjects also had CT scans of the pituitary fossa. One male patient had hypogonadotrophic hypogonadism; another had a large prolactinoma and hypothyroidism; these were excluded from the analysis. Of the remaining 48 subjects, 14 (29 per cent) had reduced TSH responses to TRH and 28 (64 per cent) decreased GH responses to L-dopa compared with our laboratory's reference ranges. Fifteen women (51 per cent) had low basal gonadotrophin levels of which 10 (34 per cent) gave a poor LH response to LHRH and eight (27 per cent) a poor FSH response. Forty-three subjects (93 per cent) gave a good ACTH response to metyrapone. Only six subjects (24 per cent) had an apparently normal pituitary fossa; 16 (64 per cent) had partially or completely empty fossas. There was no significant correlation between the diminished pituitary responses. Only one patient had responses which suggested panhypopituitarism. There was also no significant correlation between the appearance on CT scan of the pituitary fossa and the results of the dynamic tests. It is suggested that laboratory reference range for pituitary function which have been derived from young ambulatory subjects are not appropriate for hospital in-patients over the age of 75. A series of reference ranges for such subjects is proposed.

Aged↗
PubMed2001

Autoimmune hypothyroidism coexisting with a pituitary adenoma secreting thyroid-stimulating hormone, prolactin and alpha-subunit.

A 44-year-old woman presented to her GP with excessive tiredness. She had positive thyroid microsomal and thyroglobulin autoantibodies and was found to have an elevated serum thyroid-stimulating hormone (TSH) concentration of 8.37 (normal = 0.15-3.5)mU/L and a low normal total thyroxine (T4) of 86 (reference range 60-145)nmol/L. She was rendered symptom free on a dose of 150 microg of thyroxine per day. However, her TSH failed to return to normal, and following a further increase in her thyroxine dose she was referred to the endocrine clinic for further assessment. Her TSH at this stage was 14mU/L, free T4 (fT4) 28 (normal = 10-27)pmol/L and free T3 (fF3) 10 (normal = 4.3-7.6)pmol/L. She denied any problems with adherence to her medication. Her serum prolactin was elevated at 861 (normal = 60-390)mU/L. A pituitary tumour was suspected and an MRI scan showed a macroadenoma of the right lobe of the pituitary, extending into the suprasellar cistern. The tumour was resected trans-sphenoidally. Electron microscopy showed a dual population of neoplastic cells compatible with a thyrotroph cell and prolactin-secreting adenoma. Immunocytochemistry and cell culture studies confirmed the secretion of TSH, prolactin and alpha-subunit. Postoperative combined anterior pituitary function tests did not demonstrate any deficiency of anterior pituitary hormones. A repeat MRI scan showed no significant residual tumour; however, her serum TSH and prolactin levels remained high and she was given a course of pituitary irradiation. This case illustrates the difficulty of diagnosing a TSHoma when it coexists with autoimmune hypothyroidism. We believe the combination of pathologies reported here is unique.

Adrenocorticotropic Hormone↗
PubMed1996

Leukemia inhibitory factor (LIF) induces acute adrenocorticotrophic hormone (ACTH) secretion in fetal rhesus macaque primates: a novel dynamic test of pituitary function.

Leukemia Inhibitory Factor (LIF), a pituitary cytokine, and LIF receptors are expressed in human fetal and adult adenohypophyseal cells. LIF induces adrenocorticotropin hormone (ACTH) secretion in vitro and potently synergizes with both corticotropin-releasing hormone (CRH) and cAMP-induced pro-opiomelanocortin (POMC) transcription. We therefore investigated the effects of intra-carotid administration of recombinant human LIF to chronically catheterized fetal non-human primates. LIF induced fetal monkey ACTH secretion in a time- and dose dependent manner. Maximal ACTH induction (12-fold) was achieved with 100 micrograms/kg after 60 minutes (p < 0.01). CRH (10 micrograms/kg) also induced ACTH secretion 4.8-fold at 60 minutes. Co-injection of LIF (50 micrograms/kg) and CRH (10 micrograms/kg) synergistically induced ACTH levels in a time-dependent manner up to 23-fold after 60 minutes. Thus, LIF alone induces ACTH secretion and LIF acts in synergy with CRH in vivo. As LIF is expressed early in human fetal pituitary development, and potentiates corticotroph function both in vitro and in vivo, this immuno-regulatory cytokine may be useful for clinical testing of the hypothalamic-pituitary-adrenal axis.

Adrenocorticotropic Hormone↗
PubMed1977

[Clinical evaluation on glucocorticoid administration in neurosurgical patients (author's transl)].

Anterior pituitary function tests (ITT, TRH test and LH-RH test) were performed on 10 patients with intracranial lesions other than hypothalamo-pituitary tumors. These lesions were 8 brain tumors and 2 aneurysms. Relatively high doses of glucocorticoid were administered in pre- and post-operative period to all the cases. Preoperative study showed a slightly low response of GH and FSH in one case and a low TSH response in 2 cases. ACTH, LH and PRL were normal in all the cases. Postoperative study was performed about 10 days after ceasing of glucocorticoid. Postoperative data revealed that anterior pituitary function tests did not show any significant changes after surgeries in all the patients.

Adult↗