ABSTRACT
The selective alpha1 -adrenoceptor antagonist doxazosin has apparently beneficial effects on insulin sensitivity and on plasma lipid concentrations. In order to understand these effects better, we investigated the acute effects of doxazosin on adipose tissue and forearm blood flow and on postprandial lipid metabolism in healthy subjects. Nine subjects were studied in a balanced, placebo-controlled design. Pulse rate, blood pressure, forearm and subcutaneous adipose tissue blood flow were measured before and for 6 h after a mixed meal, with concomitant measurements of blood metabolites and insulin. Doxazosin increased pulse rate (p = 0.02) and forearm blood flow (p < 0.01 in fasting state), and decreased vascular resistance in forearm (p < 0.05 for fasting values) and subcutaneous abdominal adipose tissue (p = 0.04). Fasting plasma non-esterified fatty acid concentrations were increased by 40 % (p < 0.05). No other metabolic effects were detected. The effects on adipose tissue vascular resistance and lipolysis (reflected in elevated non-esterified fatty acid concentrations) were unexpected, as these are usually considered to be mediated by the balance of alpha2 - and beta-adrenoceptor activity in humans. We conclude that alpha1 -adrenoceptor activity may be more important in regulation of human lipid metabolism than previously recognized.
Subject(s)
Adrenergic alpha-Antagonists/administration & dosage , Doxazosin/administration & dosage , Fatty Acids, Nonesterified/blood , Hemodynamics/drug effects , Adipose Tissue/metabolism , Adult , Blood Pressure/drug effects , Fasting , Female , Forearm/blood supply , Heart Rate/drug effects , Humans , Male , Middle Aged , Postprandial Period , Regional Blood Flow/drug effects , Triglycerides/bloodSubject(s)
Potassium/blood , Specimen Handling/methods , Temperature , Bias , England , Family Practice , Hospitals, Urban , Humans , Potassium/metabolism , Reproducibility of ResultsABSTRACT
Biochemical changes that had appeared after subtotal parathyroidectomy (PTx) in 26 patients with end-stage renal failure were observed. The volume of excised parathyroid glands was also measured. Serum calcium and inorganic phosphorus levels fell after PTx; only to rise in due course. Serum alkaline phosphatase levels rose after PTx, reaching a peak by the 14th post-operative day. These elevated levels returned to normal range at about three months after PTx. Strong correlation was noted among the degree of post-operative hypocalcemia, and increase in serum alkaline phosphatase, but not between absolute pre or post-operative alkaline phosphatase levels and changes in serum calcium or phosphorus concentrations. Nevertheless, significant correlation was seen between pre-PTx levels of alkaline phosphatase and its short-lived post-operative rise, indicating hastened osteoblastic activity.
