Adrenocorticotropin and melanocyte-stimulating hormone in the brain.
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Biomedical subjects
Publications and source records attributed to J W Kendall.
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The ACTH-cortisol axis was studied in 15 hemodialysis patients. Basal plasma cortisol concentrations were found to be elevated and ACTH to be in the high normal range. Cortisol responded normally to exogenous ACTH, but neither cortisol nor ACTH were suppressed in response to oral dexamethasone. 11-Deoxycortisol and ACTH concentrations did not rise normally in response to either oral or iv metyrapone. We conclude that standard testing of the ACTH-cortisol axis in dialysis patients yields results suggesting Cushing's syndrome.
Large, adrenocorticotrophic hormone-secreting pituitary tumors (Nelson's syndrome) developed in four of 12 patients treated with a bilateral adrenalectomy for Cushing's disease. Two of the patients with Nelson's syndrome suffered spontaneous pituitary tumor infarctions. One patient improved under close observation and subsequent radiation therapy, although she ultimately died from her locally invasive tumor. The condition of the other patient-which had stabilized-appeared to be worsened by surgical intervention. The high incidence of these tumors after bilateral adrenalectomy, their large and agressive nature, and their apparent propensity to undergo spontaneous infarction supports the position that initial therapy for Cushing's disease should be directed to the pituitary gland.
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Plasma and cerebrospinal fluid (CSF) specimens from 3 patients with suprasellar extension of a pituitary tumour were fractionated by column chromatography. "Big" and "little" prolactin were found in plasma but only "little" prolactin was found in CSF. Prolactin containing CSF from 2 of the patients was incubated with prolactin-free plasma and chromatographed. The elution patterns demonstrated a striking shift toward the [125I]albumin marker resembling the "big" and "little" prolactin pattern seen in native plasma. In addition, [125I]h prolactin was incubated with prolactin-free plasma and rechromatographed. A substantial early eluting peak of radioactivity occurred in the zone of albumin elution. The presence of only "little" prolactin in CSF and the conversion of CSF "little" prolactin to "big" prolactin by exposure to plasma suggest that "big" prolactin is not a prohormone but results from binding of "little" prolactin to plasma proteins or aggregation of "little" prolactin in the presence of plasma.
Twelve cases of the primary empty sella syndrome were analyzed in regard to clinical findings, roentgenographic features, pituitary function and cerebrospinal fluid adenohypophysial hormone concentration. The findings were compared with those in 247 cases of the primary empty sella syndrome reviewed from the literature in order to determine the major characteristics of this disorder. The majority of patients are obese, multiparous women with normal pituitary reserve, normal visual fields and undetectable adenohypophysiol hormone concentrations in cerebrospinal fluid. In addition occasional patients witll have hypertension, pseudotumor cerebri and cerebrospinal fluid rhinorrhea. Patients who present with the typical features of the primary empty sella syndrome should be evaluated periodically with pituitary function testing, visual field examinations and cerebrospinal fluid adenohypophysial hormone determinations. If these parameters remain normal during careful follow-up studies, the patient is likely to have an empty sella, and pneumoencephalographic and angiographic studies can be avoided.
In order to define nyctohemeral plasma ACTH secretory patterns, frequency plasma ACTH samples were obtained in seven patients with untreated Cushing's disease (i.e. pituitary-dependent Cushing's syndrome), five Cushing's patients treated by bilateral adrenalectomy, four of whom had Nelson's syndrome, and one patient with 21-hydroxylase deficiency (congenital adrenal hyperplasia). A nyctohemeral rhythm of plasma ACTH concentration was apparent in the one patient with the adrenogenital syndrome but not in those with Nelson's syndrome or Cushing's disease. The effect of graded doses of dexamethasone, 2,8 or 32 mg per 24 h period, on plasma ACTH concentrations was studied in patients with untreated or treated Cushing's disease or Nelson's syndrome. In all of these hypercorticotrophic states, the mean plasma ACTH concentraton was not significantly affected by the smallest dose of dexamethasone, was partially suppressed by the intermediate dose, and further suppressed by the largest dose. In contrst, the patient with congenital adrenal hyperplasia and elevated plasma ACTH concentrations showed complete suppression of plasma ACTH levels following the smallest dose of dexamethasone. These findings indicate that there is resistance to ACTH suppression by dexamethasone in all stages of Cushing's disease and suggest that negative feedback of glucocorticoids may be involved in the pathogenesis of this disease.
A 17-year-old women received 12,000 rads of alpha-particle radiation for the treatment of Cushing's disease. One day after the completion of therapy, the patient developed nausea, vomiting, headache, and postural hypotension. Laboratory evaluation demonstrated a marked fall of the previously elevated urinary 17-hydroxycorticosteroids (17-OHCS) and undetectable plasma cortisols. The urinary 17-OHCS transiently returned to supranormal levels but over a 2 1/2-week period decreased and then remained low. The patient also demonstrated a subnormal urinary aldosterone excretion in relation to plasma renin activity (PRA) during 10 mEq/24 h sodium restriction. The remainder of the endocrine evaluation was normal, suggesting that pituitary function otherwise remained intact. One and one-half years after alpha-particle therapy, the patients's urinary 17-OHCS were normal and responded normally to metyrapone. The relationship between urinary aldosterone excretion and PRA also was normal. It is postulated that there was an infarction of an ACTH secreting pituitary tumor leaving the remainder of the pituitary intact. Achronically elevated circulating level of ACTH with sudden loss of ACTH secretion appeared to have been responsible for the initial low urinary aldosterone as well as the low urinary 17-OHCS. This is the first reported case of a presumed pituitary tumor infarction in association with alpha-particle pituitary radiation.
The ACTH-releasing activity of hypothalamic extract and rat plasma was examined with the dispersed rat pituitary cell technique of Swallow and Sayer (8). Although both plasma and serum caused ACTH release which was dose-related, stress did not enhance the ACTH releasing activity. Furthermore, separation studies of plasma using ultrafiltration and gel separation suggest that the CRF activity in plasma is associated with molecules of a molecular weight greater than 15,000.
Cerebrospinal fluid (CSF) concentrations of corticotropin, growth hormone, thyrotropin, prolactin, luteinizing hormone, and follicle stimulating hormone were measured in 28 patients with various neurologic disorders, in 49 patients with pituitary tumors of whom 22 had suprasellar extension, and in 6 patients with craniopharyngiomas. With the exception of 1 patient with pseudotumor cerebri, CSF adenohypophyseal hormone concentrations were low in patients with neurologic disease and in patients with pituitary tumor without suprasellar extension. In marked contrast, 21 to 22 patients with suprasellar extension of a pituitary tumor and 2 of 6 patients with a craniopharyngioma had elevations of one or more CSF adenohypophyseal hormones. Posttreatment CSF adenohypophyseal hormone levels fell from previously elevated levels in 4 of 5 patients. These data suggest that an elevated CSF adenohypophyseal hormone concentration is a sensitive indicator of suprasellar extension of a pituitary tumor, and posttreatment measurements are useful in determining efficacy of therapy.