title: Overnight suppression of parathyroid hormone and bone resorption markers by active absorbable algae calcium. A double-blind crossover study.
abstract: In order to study the effect of Ca supplementation on the nocturnal rise of PTH and bone resorption, a double-blind, placebo-controlled study was carried out on 9 healthy male volunteers. Regimen A consisted of an oral dose of 150 mg Ca as AAACa after each meal and 450 mg at bedtime; B consisted of 300 mg after each meal and C was placebo. Plasma ionized Ca was significantly higher in A than in B at 6 a.m. the next morning and urinary Ca/Cr after 5 days was higher in A than in B and C. Plasma intact PTH fell by 19 +/- 4 pg/ml in A, 8 +/- 7 in B, and 1 +/- 7 after 1 day, and significantly decreased by 29 +/- 8 in A, increased by 11 +/- 11 in B, and 5 +/- 7 in C after 5 days (A and B, and A and C, p = 0.0242 and 0.0433, respectively), with increases of % tubular reabsorption of phosphorus. Urinary excretion of cross-linked collagen degradation product (Crosslaps) was 40 +/- 10% of the baseline in A, 97 +/- 22 in B, and 173 +/- 30 in C (A and C, P = 0.0061) after 5 days. Systolic blood pressure at 6 a.m. fell by 17 +/- 4 mmHg A, 24 +/- 3 in B, and 4 +/- 2 in C. Highly biologically available AAACa effectively suppressed nocturnal rise of PTH and bone resorption markers in 5 days.
authors.affiliation: Calcium Research Institute, 250 Makamicho, Kishiwada, Osaka 596, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Fujita
authors.forename: S
authors.initials: S
authors.lastname: Ohgitani
authors.forename: Y
authors.initials: Y
authors.lastname: Fujii
mesh_terms: D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood*; D001794:Blood Pressure / Q000187:drug effects; D001862:Bone Resorption / Q000097:blood*; D002118:Calcium / Q000097:blood* / Q000652:urine; D002136:Calcium, Dietary / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D002940:Circadian Rhythm; D003404:Creatinine / Q000097:blood / Q000652:urine; D018592:Cross-Over Studies; D004311:Double-Blind Method; D056890:Eukaryota; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects / Q000502:physiology; D007564:Japan; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D011188:Potassium / Q000097:blood / Q000652:urine; D011863:Radioimmunoassay; D012964:Sodium / Q000097:blood / Q000652:urine
chemical_list: D015415:Biomarkers; D002136:Calcium, Dietary; D010281:Parathyroid Hormone; D012964:Sodium; D003404:Creatinine; D011188:Potassium; D002118:Calcium