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Blood levels of many hormones show rhythmic fluctuations with variable duration of cycles. Clusterin/apolipoprotein J is a glycoprotein which is highly expressed in the plasma and has modulatory roles in immune and inflammatory reactions, neurobiology, lipid metabolism, and leptin signaling. In this study, we examined the diurnal fluctuations of plasma clusterin concentrations in lean and obese young men.
For the study, 14 subjects (five lean and five obese men; two lean and two obese women) were admitted to the research ward and blood samples were drawn every 30 minutes during light-on period (6:00 AM to 10:00 PM) and every hour during light-off period.
Notably, plasma clusterin concentrations displayed a unique ultradian rhythm with five cycles a day in both men and women. During the light-on period, circulating clusterin levels showed fluctuating curves with 4 hours regular intervals with sharp peaks and troughs. In contrast, single oscillation curve during light-off exhibited a smoothened/lower peak and longer (8-hour) duration. In obese men, these cycles were phase-advanced by approximately 1 hour, and had reduced amplitude of fluctuating curves and blunted diurnal pattern. Cyclic fluctuations of plasma clusterin were preserved under fasting and unexpected meal condition, suggesting that rhythmic oscillations in plasma clusterin levels are not generated by meal-related cues.
These findings firstly demonstrate a novel pattern of plasma clusterin fluctuations with extremely regular cycles.
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In healthy individuals, energy intake is in balance with energy expenditure, which helps to maintain a normal body weight. The brain's inability to control energy homeostasis underlies the pathology of hyperphagia and obesity. The brain detects body energy excess and deficit by sensing the levels of circulating metabolic hormones and nutrients and by receiving metabolic information from the periphery via the autonomic nervous system. A specialized neuronal network coordinates energy intake behavior and the metabolic processes affecting energy expenditure. Here, we briefly review neuronal mechanisms by which our body maintains energy balance.
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Cushing's disease (CD) is a rare disorder characterized by the overproduction of adrenocorticotropic hormone due to a pituitary adenoma that ultimately stimulates excessive cortisol secretion from the adrenal glands. Prior to the detection of pituitary adenomas, various clinical signs of CD such as central obesity, moon face, hirsutism, and facial plethora are usually already present. Uncontrolled hypercortisolism is associated with metabolic, cardiovascular, and psychological disorders that result in increased mortality. Hence, the early detection and treatment of CD are not only important but mandatory. Because its clinical manifestations vary from patient to patient and are common in other obesity-related conditions, the precise diagnosis of CD can be problematic. Thus, the present set of guidelines was compiled by Korean experts in this field to assist clinicians with the screening, diagnoses, and treatment of patients with CD using currently available tests and treatment modalities.
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Acromegaly is a slowly progressing condition resulting from excess growth hormone (GH), generally caused by a GH-secreting pituitary adenoma. Cancer is the third most common cause of mortality in patients with acromegaly, and insulin-like growth factor 1 (IGF-1) is known to influence tumor formation by increasing cell proliferation and inhibiting apoptosis. Multiple myeloma (MM) is a plasma cell neoplasm, and previous studies have suggested the possible role of IGF-1 in its development of MM. However, no cases of acromegaly accompanied with MM have been reported in Asia to date. We here report the case of a 58-year-old woman with acromegaly accompanied with MM who presented with longstanding acromegalic manifestations resulting from a GH-secreting pituitary adenoma and also exhibited anemia, a reversed albumin/globulin ratio, and plasmacytosis on bone marrow examination. Because IGF-1 has been suggested to play an important role in the development and progression of MM, the patient promptly underwent surgical removal of the pituitary adenoma via a transsphenoidal approach. Since there is currently no consensus on therapeutic guidelines and suggested prognosis for MM with acromegaly, long-term follow-up of such cases is needed.
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