Growth hormone (GH) exerts its effects through insulin-like growth factor-1, and although ubiquitous in human tissues, it has a significant role in cardiovascular function. In recent years, there has been a great deal of interest in GH as an etiologic factor in many cardiovascular disease states. Acromegaly, a state of endogenous GH excess, results in myocardial hypertrophy and decreased cardiac performance with increased cardiovascular mortality. Additional insight into the role of excess GH on the cardiovascular system has been gained from data collected in athletes doping with GH. Likewise, GH deficiency is associated with increased mortality, possibly from the associated increase in atherosclerosis, lipid abnormalities, and endothelial dysfunction. However, further research is required to clarify the benefit of GH treatment in both deficient states and in heart failure patients.
Pheochromocytomas are rare endocrine tumors that can have a significant impact on a variety of organ systems, including the cardiovascular system. Although the pathophysiology is not completely understood, pheochromocytomas exert their effects through high levels of catecholamines, mainly epinephrine and norepinephrine, which stimulate adrenergic receptors, including those within the cardiovascular system. Although the most common cardiovascular manifestation is hypertension, patients with pheochromocytoma can present with arrhythmia, hypotension, shock, myocardial ischemia, cardiomyopathy, aortic dissection, and peripheral ischemia. The medical management of the cardiovascular effects of pheochromocytoma is via blockade of adrenergic receptors, usually through the use of alpha blockers, with the addition of beta blockers if needed. However, only surgical resection of the pheochromocytoma is potentially curative, and this tumor requires unique management perioperatively. Because of the variability of presentation and the significant morbidity and mortality of patients with an undiagnosed pheochromocytoma, this entity should not be overlooked in the evaluation of patients with a wide variety of cardiovascular disorders.
Lee PW, Swerdloff RS. Genetic, hormonal, and metabolomic influences on social behavior and sex preference of XXY mice. Am J Physiol Endocrinol Metab 299: E446-E455, 2010. First published June 22, 2010; doi:10.1152/ajpendo.00085.2010.-XXY men (Klinefelter syndrome) are testosterone deficient, socially isolated, exhibit impaired gender identity, and may experience more homosexual behaviors. Here, we characterize social behaviors in a validated XXY mouse model to understand mechanisms. Sociability and gender preference were assessed by three-chambered choice tasks before and after castration and after testosterone replacement. Metabolomic activities of brain and blood were quantified through fractional synthesis rates of palmitate and ribose (GC-MS). XXY mice exhibit greater sociability than XY littermates, particularly for male mice. The differences in sociability disappear after matching androgen exposure. Intact XXY, compared with XY, mice prefer male mice odors when the alternatives are ovariectomized female mice odors, but they prefer estrous over male mice odors, suggesting that preference for male mice may be due to social, not sexual, cues. Castration followed by testosterone treatment essentially remove these preferences. Fractional synthesis rates of palmitate are higher in the hypothalamus, amygdala, and hippocampus of XXY compared with XY mice but not with ribose in these brain regions or palmitate in blood. Androgen ablation in XY mice increases fractional synthesis rates of fatty acids in the brain to levels indistinguishable from those in XXY mice. We conclude that intact XXY mice exhibit increased sociability, differences in gender preference for mice and their odors are due to social rather than sexual cues and, these differences are mostly related to androgen deficiency rather than genetics. Specific metabolic changes in brain lipids, which are also regulated by androgens, are observed in brain regions that are involved in these behaviors.aneuploidy; Klinefelter syndrome; testosterone; X-inactivation; brain lipids KLINEFELTER SYNDROME (KS) was first described in 1942 and its chromosomal etiology identified in 1959 (11, 16). It is the most frequent sex chromosome aneuploidy in human males, with an incidence of 1 in 500 male conceptions and 1 in 800 -1,000 live male births (3,22,34). KS patients are males with an extra X chromosome (XXY), and the syndrome is typified by reproductive dysfunction such as androgen deficiency and associated sexual dysfunction, small testicular size, gynecomastia, delayed onset of puberty, infertility, and tall stature as well as nonreproductive characteristics, including dyslexia, slowed learning, and social isolation (17,40,42). KS males also exhibit higher rates of attention deficit hyperactivity disorder (AD/HD) and psychiatric diseases such as schizophrenia and depression. These clinical and behavioral features of KS could be explained as genetic and/or hormonal (testosterone deficiency). Others have also suggested that KS is a useful model to dissect the genetic ba...
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