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During the period 1952 to 1976 at Vanderbilt University Hospital 119 patients with pituitary-dependent hypercortisolism or Cushing's disease were studied. The less severe cases, which constitute a majority, were treated by pituitary irradiation with endocrinologic cure or improvement in two-thirds of the treated patients. Bilateral total adrenalectomy was reserved for the most severe cases and for failures of pituitary irradiation. In 29 patients with total bilateral adrenalectomy there was one postoperative death. Two of 28 survivors had incomplete relief of hypercortisolism and required additional therapy for its control. One patient with recent operation is improved and another with early improvement died suddenly at home three months after operation. The 24 other adrenalectomized patients, followed 6 months to 20 years, were considered endocrinologic cures of Cushing's disease. One patient in the group who had not received pituitary irradiation developed signs of expanding pituitary tumor after adrenalectomy (Nelson's syndrome) with satisfactory response to radiation therapy.

The blood pressure elevation of primary aldosteronism is caused by excessive production of the known mineralocorticoid, aldosterone. The blood pressure elevation of low-renin essential hypertension may also be caused by mineralocorticoid excess, but which which mineralocorticoid is responsible is uncertain. Normal levels of aldosterone, found in this disorder despite suppressed plasma renin, and the presence of an unknown mineralocorticoid have been hypothesized to explain low-renin essential hypertension. We contrasted the blood pressure responses and changes in aldosterone seen in patients with low-renin essential hypertension and primary aldosteronism during treatment with two adrenal enzyme inhibitors. The results demonstrate the similarity between decrease in blood pressure and in aldosterone during early adrenal inhibition in both primary aldosteronism and in low-renin essential hypertension. During treatment with a distal adrenal blocker, patients with primary aldosteronism demonstrated decreases in both aldosterone and blood pressure, whereas patients with low-renin essential hypertension showed a decrease in aldosterone without significant change in blood pressure. This suggested that aldosterone was not the major mineralocorticoid responsible for low-renin essential hypertension. Unknown mineralocorticoid excretion decreased (along with blood pressure) during early inhibition but failed to decrease (along with blood pressure) during late inhibition at a time when aldosterone excretion decreased. This suggests that unknown mineralocorticoids play significant roles in the blood pressure elevation of low-renin essential hypertension.

The possibility that dopamine may play a role in the in vivo control of aldosterone production in man was suggested to us by reports from others; (a) that bromocriptine, a dopaminergic agonist, inhibits the aldosterone response to diuresis and to the infusion of angiotensin or ACTH; and (b) that metaclopramide, a dopamine blocking agent, causes elevations in plasma aldosterone levels. To determine whether such effects were direct or indirect, we examined the action of dopamine on aldosterone biosynthesis in isolated, bovine adrenal cells. Dopamine significantly inhibits the aldosterone response to angiotensin (P < 0.001), but does not influence basal aldosterone biosynthesis. It has previously been reported that angiotensin stimulates both the early and late phases of aldosterone biosynthesis. The present experiments demonstrated that the enhancing effect of angiotensin on the conversion of deoxycorticosterone to aldosterone (late phase of aldosterone biosynthesis) was almost completely inhibited by dopamine (P < 0.001). A significant inhibitory effect of dopamine (10 nM) was seen even when aldosterone biosynthesis was stimulated by a grossly supraphysiological concentration of angiotensin II (10 muM). However, these studies did not demonstrate any direct effect of dopamine on the early phase of aldosterone biosynthesis (cholesterol to pregnenolone) basally or when stimulated, or on the late phase of aldosterone biosynthesis under basal conditions. These in vitro studies suggest a direct inhibitory role for dopamine on the late phase of aldosterone biosynthesis, which may account for the in vivo inhibition of the aldosterone response to angiotensin in subjects treated with a dopaminergic agent.

Eight normal male volunteers received an LHRH analog, 100 to 500 micrograms daily, for 20 weeks. Testosterone enanthate, 100 mg, was given by injection every second week. Sperm density fell to 5.5 X 10(6)/ml and to 0 in two of the subjects receiving 100 micrograms, but was unchanged in the third. Three of the subjects who received 500 micrograms displayed azoospermia, whereas the other two showed no significant change in sperm density. The reasons for the heterogeneity are not clear. Only one of the three nonresponders had testosterone values that were higher than the other subjects. Gonadotropin levels were similar in responders and nonresponders. It is possible that the response to LHRH analog in man is determined by the extent of the reduction in LH bioactivity.

Studies were undertaken to determine what part of the aldosterone biosynthetic pathway is stimulated by angiotensin and potassium. The availability of a method for isolating the early portion of the aldosterone pathway and a new method for measuring plasma deoxycorticosterone permitted the design of experiments to determine whether angiotensin and potassium stimulate the pathway before deoxycorticosterone. To eliminate ACTH-dependent steroid synthesis, the experiments were performed in subjects receiving constant dosage of dexamethasone. To minimize the intra-adrenal conversion of deoxycorticosterone to corticosterone, all subjects also received constant dosage of metyrapone. Plasma deoxycortisol was measured as an index of the activity of the zona fasciculata. In the absence of changes in plasma deoxycortisol, one may infer that changes in plasma deoxycorticosterone represent changes in function of zona glomerulosa, the site of aldosterone formation. Under these conditions, human subjects responded both to angiotensin and to potassium with significant increases in plasma deoxycorticosterone but without significant increases in plasma deoxycortisol. In contrast, small doses of ACTH given under similar conditions never induced increases in plasma deoxycorticosterone without simultaneously inducing large increases in plasma deoxycortisol. It is concluded that the aldosterone-stimulating effects of angiotensin and potassium are, at least in part, consequences of stimulation of the biosynthetic pathway at some point before the formation of deoxycorticosterone so as to increase the availability of aldosterone precursors.

Glucagon activates hepatic adenylate cyclase, thereby increasing acutely the liver content of cyclic AMP (cAMP) as well as the release of cAMP into the hepatic vein. Insulin, on the other hand, antagonizes this glucagon-mediated cAMP production, thus providing a hypothetical mechanism through which insulin might correct some of the metabolic abnormalities of diabetes. To study this hormonal interaction in man, net splanchnic cAMP production (NScAMPP) was investigated in normal and insulin-dependent diabetic men under basal conditions and in response to intravenous glucagon, 50 ng/kg/min for 2 h. In normals (n=19), basal hepatic vein cAMP concentration was 23.6+/-1.1 nM and NScAMPP was 1.7+/-0.6 nmol/min. Glucagon stimulated NScAMPP in four normal subjects to a peak of 99.6+/-43 nmol/min at 25 min with a subsequent fall to 12.4+/-5.1 nmol/min by 90 min despite continuing glucagon infusion. Endogenous insulin secretion was stimulated as indicated by rising levels of immunoreactive insulin and C-peptide (connecting peptide) immunoreactivity, raising the possibility that endogenous insulin might be responsible for the fall in NScAMPP that followed the initial spike. In the diabetics (n=8), basal hepatic vein cAMP concentration was 24.7+/-1.2 nM and NScAMPP was undetectable. Glucagon stimulated NScAMPP in five diabetics to a peak of 169.9+/-42.6 with a subsequent fall to 17.4+/-3.9 nmol/min by 90 min even though endogenous insulin secretion was not stimulated (no rise in C-peptide immunoreactivity). Although the mean increase in NScAMPP was greater in the diabetics, the two groups did not differ significantly.Conclusions. In normal resting man the liver is a significant source of circulating cAMP. Diabetics do not release abnormally large amounts of hepatic cAMP under basal conditions. Glucagon markedly enhances hepatic cAMP release with a spike-decline pattern in both normal and diabetic men. The decline in hepatic cAMP release despite continuing glucagon stimulation is due to factors other than a stimulation of insulin secretion.

The regulation of plasma beta-melanocyte-stimulating hormone (beta-MSH) in man has been studied utilizing a radioimmunoassay previously described (1). In normal subjects plasma beta-MSH values ranged from 20 to 110 pg/ml. Metyrapone increased and dexamethasone decreased plasma beta-MSH levels. Surgical stress stimulated beta-MSH secretion. Plasma beta-MSH levels were elevated in patients with untreated Addison's disease and untreated congenital adrenal hyperplasia, and these levels fell to normal during glucocorticoid therapy. In patients with Cushing's syndrome due to pituitary adrenocorticotropic hormone (ACTH) excess, plasma beta-MSH was slightly elevated before treatment. In those patients who developed pituitary tumors and hyperpigmentation after bilateral adrenalectomy, plasma beta-MSH was greatly elevated. In patients with Cushing's syndrome due to adrenal tumor, plasma beta-MSH was subnormal. In patients with the ectopic ACTH syndrome, the levels of plasma beta-MSH were high. Plasma beta-MSH had a diurnal variation in normal subjects, patients with Addison's disease, and patients with congenital adrenal hyperplasia; but the normal diurnal variation was lost in patients with Cushing's disease. In patients with high plasma beta-MSH, simultaneous determinations of plasma ACTH showed close correlation between the degree of elevation of ACTH and that of beta-MSH. In extracts of tumors from patients with the ectopic ACTH-MSH syndrome the quantities of the two hormones were roughly equivalent. In patients with hyperpigmentation due to a variety of disorders other than pituitary-adrenal abnormalities, plasma beta-MSH was normal. It is concluded that the secretion of beta-MSH is regulated by the same factors that regulate ACTH.

Six patients who had experienced prolonged steroid-induced pituitary-adrenal suppression were treated with 100 U of depot procine ACTH every 2 to 4 days for several months. Such treatment did not hasten the recovery of normal pituitary-adrenal function compared with the rate of recovery of a group of similarly suppressed patients who received no depot ACTH. Eight of nine patients who received prolonged courses of depot porcine ACTH developed antibodies to ACTH that cross-reacted with endogenous ACTH, binding it in the circulation in inactive form and retarding its removal from the circulation. The presence of such antibodies did not in itself grossly alter pituitary-adrenal interrelationships.

The effects of parathyroid hormone (PTH) on plasma and urinary adenosine 3',5'-monophosphate (cyclic AMP) levels were studied in normal subjects. Under basal conditions normal adults have plasma concentrations of cyclic AMP ranging from 10 to 25 nmoles/liter and excrete from 1.5 to 5 mumoles of cyclic AMP per g of urinary creatinine. About one-half to two-thirds of the cyclic AMP excreted in the urine is derived from the plasma by glomerular filtration, and the remainder is produced by the kidney. Renal production of cyclic AMP is partly under the control of PTH. It can be suppressed by infusions of calcium and stimulated by infusions of the calcium chelating agent, EDTA. Infusions of PTH in doses up to 10 mU/kg per min were associated with dose-related increases both in urinary cyclic AMP and phosphate. Infusions of PTH in doses ranging from 20 to 80 mU/kg per min did not lead to any further increase in phosphaturia but did lead to further marked increases in urinary cyclic AMP. A modest increase in plasma cyclic AMP was noted when PTH was infused at 40 mU/kg per min. Anephric patients failed to show appreciable increases in plasma cyclic AMP in response to large doses of PTH but did show expected increases in response to glucagon. Surgical removal of parathyroid adenomas from nine patients with primary hyperparathyroidism was invariably followed by a decrease in urinary cyclic AMP, PTH, in large doses, and calcium infusion produced up to 2-fold increases in the other known naturally occurring cyclic nucleotide, guanosine 3',5'-monophosphate (cyclic GMP).

A radioimmunoassay method for beta-melanocyte-stimulating hormone (beta-MSH) has been developed and utilized in the identification and quantification of this hormone in human plasma and tissues. The concentration of beta-MSH in two human pituitary glands was found to be approximately 350 mug/g. beta-MSH was identified in the tumor tissue of all 11 patients with the ectopic ACTH syndrome who were studied; concentrations in individual cases ranged from 3 to 1600 ng/g. In plasma of chronically hyperpigmented patients with Addison's disease, Cushing's disease (after bilateral adrenalectomy), and the ectopic ACTH syndrome, beta-MSH concentrations of 0.5-6 ng/ml were found. The degree of clinical hyperpigmentation was well correlated with the quantity of beta-MSH in the plasma. beta-MSH concentrations in the plasma of normal subjects were less than 0.09 ng/ml. In all of these circumstances, bioassays for MSH were also performed, and it was found that most of the biologic MSH activity of the plasma and tissues could be accounted for by beta-MSH.

Glucagon, infused intravenously into fasting, well-hydrated, normal men in doses of 25-200 ng/kg per min, induced up to 30-fold increases in both plasma and urinary cyclic AMP. Cyclic GMP levels were unaffected by glucagon. Simultaneous cyclic AMP and inulin clearance studies demonstrated that the glucagon-induced increase in urinary cyclic AMP was entirely due to glomerular filtration of the elevated plasma levels of the nucleotide. The cyclic AMP response to glucagon was not mediated by parathyroid hormone or epinephrine, and trypsintreated glucagon was completely inactive. The perfused rat liver released cyclic AMP into the perfusate in response to glucagon, indicating that the liver is a possible source of the cyclic AMP entering the extracellular fluids in response to glucagon in vivo.

The comparative effects of angiotensin II and adrenocorticotropic hormone (ACTH) on cyclic AMP and steroidogenesis were investigated employing isolated bovine adrenal cells from the zona fasciculata. Like ACTH, angiotensin produced a prompt increase in cyclic AMP which preceded the increase in corticosteroid production. Although this increase in cyclic AMP was small when compared to that induced by ACTH, it correlated with the amount of steroidogenesis. This observation is consistent with the view that cyclic AMP is the intracellular mediator of the steroidogenic action of angiotensin. Angiotensin acted synergistically with ACTH on cyclic AMP levels. This synergism was not explained by inhibition of phosphodiesterase activity. Unlike ACTH, angiotensin failed to stimulate adenylate cyclase in broken cell preparations. The observations suggest that more than one mechanism may be involved in effects of ACTH and angiotensin on cyclic AMP levels.

Kinetic parameters and the renal clearances of plasma adenosine 3',5'-monophosphate (cyclic AMP) and guanosine 3',5'-monophosphate (cyclic GMP) were evaluated in normal subjects using tritium-labeled cyclic nucleotides. Each tracer was administered both by single, rapid intravenous injection and by constant intravenous infusion, and the specific activities of the cyclic nucleotides in plasma and urine were determined. Both cyclic AMP and cyclic GMP were cleared from plasma by glomerular filtration. The kidney was found to add a variable quantity of endogenous cyclic AMP to the tubular urine, amounting to an average of approximately one-third of the total level of cyclic AMP excreted. Plasma was the source of virtually all of the cyclic GMP excreted. Plasma levels of the cyclic nucleotides appeared to be in dynamic steady state. The apparent volumes of distribution of both nucleotides exceeded extracellular fluid volume, averaging 27 and 38% of body weight for cyclic AMP and cyclic GMP, respectively. Plasma production rates ranged from 9 to 17 nmoles/min for cyclic AMP and from 7 to 13 nmoles/min for cyclic GMP. Plasma clearance rates averaged 668 ml/min for cyclic AMP and 855 ml/min for cyclic GMP. Approximately 85% of the elimination of the cyclic nucleotides from the circulation was due to extrarenal clearance.

The effect of glucagon (50 ng/kg/min) on arterial glycerol concentration and net splanchnic production of total ketones and glucose was studied after an overnight fast in four normal and five insulin-dependent diabetic men. Brachial artery and hepatic vein catheters were inserted and splanchnic blood flow determined using indocyanine green. The glucagon infusion resulted in a mean circulating plasma level of 4,420 pg/ml. In the normal subjects, the glucagon infusion resulted in stimulation of insulin secretion indicated by rising levels of immunoreactive insulin and C-peptide immunoreactivity. Arterial glycerol concentration (an index of lipolysis) declined markedly and net splanchnic total ketone production was virtually abolished. In contrast, the diabetic subjects secreted no insulin (no rise in C-peptide immunoreactivity) in response to glucagon. Arterial glycerol and net splanchnic total ketone production in these subjects rose significantly (P=<0.05) when compared with the results in four diabetics who received a saline infusion after undergoing the same catheterization procedure.Net splanchnic glucose production rose markedly during glucagon stimulation in the normals and diabetics despite the marked rise in insulin in the normals. Thus, the same level of circulating insulin which markedly suppressed lipolysis and ketogenesis in the normals failed to inhibit the glucagon-mediated increase in net splanchnic glucose production. It is concluded (a) that glucagon at high concentration is capable of stimulating lipolysis and ketogenesis in insulin-deficient diabetic man; (b) that insulin, mole for mole, has more antilipolytic activity in man than glucagon has lipolytic activity; and (c) that glucagon, on a molar basis, has greater stimulatory activity than insulin has inhibitory activity on hepatic glucose release.

Several lines of evidence have been developed indicating that the sympathetic nervous system may play a role in mediating the renal and adrenocortical secretory responses to upright posture and sodium deprivation. Despite concurrent increases in arterial blood pressure, the plasma renin activity of normal subjects increased both in response to the infusion of catecholamines (norepinephrine: epinephrine, 10:1) and in response to stimulation of the sympathetic nervous system by cold. Aldosterone excretion was also increased by catecholamine infusion. In normal subjects the stimuli of upright posture and of sodium depletion both resulted in increases in urinary catecholamines, plasma renin activity, and urinary aldosterone. A patient with severe autonomic insufficiency did not experience normal elevations of urinary catecholamines, plasma renin activity, or urinary aldosterone in response to upright posture or sodium deprivation, despite a substantial fall in arterial blood pressure. When orthostatic hypotension was prevented by infusion of catecholamines, however, increases in plasma renin activity and in aldosterone excretion were observed. We suggest that both upright posture and sodium depletion lead to decreases in effective plasma volume and increases in sympathetic nervous system activity. This increase in sympathetic activity is then responsible for an increase in renal afferent arteriolar constriction, leading to an increase in renin secretion and, ultimately, an increase in aldosterone secretion.

Extracts of tumors from 32 patients with the ectopic ACTH syndrome were subjected to simultaneous bioassay and radioimmunoassays for ACTH. Radioimmunoassays were performed using three antisera, one of which reacts with the extreme N-terminal 1-13 amino acid sequence of ACTH, the second with the N-terminal 1-23 sequence of the ACTH molecule, and the third with the C-terminal 25-39 amino acid sequence of ACTH. There was, in general, good correlation between bioactivity and N-terminal ACTH immunoreactivity. However, there were large excesses of both extreme N-terminal and C-terminal immunoreactive materials in most tumor extracts, which were not found in extracts of three human pituitaries. Three tumor extracts were subjected to molecular sieve chromatography on Sephadex G-50 fine resin. The bioactive ACTH eluted in the same fractions as pituitary ACTH (mol wt approximately 4,500 daltons) and reacted equally in all three ACTH radioimmunoassay systems. The bioactive tumor ACTH was neutralized by incubation with the C-terminal antiserum, indicating it has an intact C-terminal sequence of amino acids. The next several fractions from the Sephadex column contained a material, mol wt approximately 3,100, which was biologically inactive and had C-terminal immunoreactivity but no N-terminal or extreme N-terminal immunoreactivity. Incubation with the N-terminal 1-23 ACTH antiserum did not adsorb these C-terminal fragments, indicating they lacked an intact sequence of amino acids in this region. A smaller ACTH fragment (mol wt approximately 1,800 daltons) eluted in still later fractions and reacted with the extreme N-terminal antiserum but not with the N-terminal or C-terminal antisera. It had no steroidogenic activity, but appeared to have significant melanocyte-stimulating activity. It is concluded that, in addition to an ACTH similar, if not identical, to pituitary ACTH, tumors of patients with the ectopic ACTH syndrome contain both N-terminal and C-terminal ACTH fragments.

Studies were performed in healthy volunteers to determine the effects of catecholamines and adrenergic-blocking agents on plasma and urinary levels of adenosine 3',5'-monophosphate (cyclic AMP) and guanosine 3',5'-monophosphate (cyclic GMP). Plasma cyclic AMP rose in response to infusions of the beta-adrenergic agent, isoproterenol, or in response to infusions of either epinephrine or norepinephrine alone or in combination with the alpha-adrenergic-blocking agent, phentolamine. Although urinary cyclic AMP also rose, the percentage increase was less than that observed in the plasma. These treatments caused no increase in plasma cyclic GMP. Plasma cyclic GMP rose in response to infusions of alpha-adrenergic agents, viz., epinephrine or norepinephrine infused together with the beta-blocking agent, propranolol. These treatments caused no increase in plasma cyclic AMP. These observations are consistent with the current concept that the actions of beta-adrenergic agents are mediated by increases in cyclic AMP formation in target tissues. Such a mediating role has not been established for cyclic GMP, but the data suggest the possibility that cyclic GMP metabolism is responsive either to alpha-adrenergic stimulation or to parasympathetic stimulation which occurs as a reflexive consequence of the pressor effect of alpha-adrenergic agents.