A patient with a prolactinoma associated with an aldosterone producing adrenal adenoma: differences in dopaminergic regulation of PRL and aldosterone secretion

Normotensive presentation in primary aldosteronism: A report of two cases

Normotensive patients with primary aldosteronism (PA) are relatively rare. Herein, we report two patients with normotensive PA and present a literature review to improve an understanding of the disease. Patient 1, a 56-year-old man, presented with recurrent hypokalemia that lasted for more than 2 years. Patient 2 was a 33-year-old man who presented with sexual dysfunction and was diagnosed with a prolactinoma combined with adrenal insufficiency and hypogonadism. Neither of these patients had hypertension that was detectable on repeated manual measurements. In both patients, a typical biological profile of PA was demonstrated that included hypokalemia with kaliuresis, elevated plasma aldosterone concentration (PAC), suppressed plasma renin concentration, and a high aldosterone-to-renin ratio. Both patients did not have sufficiently suppressed PAC on the saline infusion test, confirming the diagnosis of PA. Computed tomography of the adrenal gland and adrenal venous sampling suggested an aldosteronoma, which was confirmed by lateralized hypersecretion of aldosterone. After removal of the benign adenoma, the biochemical abnormalities were corrected. As hypertension is not necessarily a sign of PA, we propose that all patients with hypokalemia should be screened for PA in order to prevent cardiovascular complications while balancing economics and effectiveness.

A possible new syndrome with double endocrine tumors in association with an unprecedented type of familial heart-hand syndrome: a case report

Introduction

The combination of a pituitary prolactinoma and an aldosterone-producing adrenal adenoma is extremely rare. To the best of our knowledge, double endocrine tumors in association with heart-hand syndrome have not previously been reported.

Case presentation

A 21-year-old Japanese woman presented with galactorrhea and decreased visual acuity. A large pituitary adenoma with an increased level of serum prolactin was apparent by computed tomography. She additionally showed mild hypertension (136/90 mmHg) accompanied by hypokalemia. The plasma aldosterone concentration was increased. Computed tomography showed a mass in the right adrenal gland. No other tumors were found despite extensive imaging studies. Physical and radiographic examinations showed skeletal malformations of the hands and feet, including hypoplasia of the first digit in all four limbs. An atrial septal defect was demonstrated by echocardiography. Similar digital and cardiac abnormalities were detected in our patient's father, and a clinical diagnosis of hereditary heart-hand syndrome was made.

Conclusion

No established heart-hand syndrome was wholly compatible with the family's phenotype. Her father had no obvious endocrine tumors, implying that the parent of transmission determined variable phenotypic expression of the disease: heart-hand syndrome with multiple endocrine tumors from the paternal transmission or no endocrine tumor from the maternal transmission. This suggests that the gene or genes responsible for the disease may be under tissue-specific imprinting control.

Regulation of plasma aldosterone levels by metoclopramide: a reappraisal of its mechanism from dopaminergic antagonism to serotonergic agonism

It has been thought, since the late 1970s, that dopamine exerts a tonic suppression of plasma aldosterone levels in human subjects. This action, however, had not been established directly using dopamine and dopamine mimetic drugs, which do not, in fact, affect the aldosterone levels. Rather, the conclusion was arrived at indirectly, based on the increase in aldosterone levels seen with dopamine receptor blockers; metoclopramide in particular, considered at the time of its discovery in the 1960s to be a new generation dopamine antagonist. However, metoclopramide is not a pure drug and in fact, shows intermediate affinity at certain serotonin receptor subtypes. Studies have been recently carried out in human subjects on the role of serotonergic transmission in mediating the metoclopramide as an aldosterone secretagogue effect. Here we briefly review this work and attempt to reassess the action of metoclopramide as an aldosterone secretagogue, from dopamine D2 antagonism to serotonin 5-HT4 partial agonism.