C. Catini et al., CIRCADIAN PATTERNS IN HISTAMINE CONCENTRATIONS AND MAST-CELL NUMBER IN THE RAT-THYROID GLAND, International archives of allergy and immunology, 105(4), 1994, pp. 386-390
We carried out a cross-sectional chronobiological investigation on blo
od histamine, thyroid histamine and thyroid mast cell number in Wistar
rats. Daily, blood histamine varied from 0.38+/-0.01 (12.00h) to 0.60
+/-0.01 mg/g wet weight (20.00 h) and thyroid histamine from 21.2+/-1.
19 (04.00 h) to 38.3+/-1.54 mg/g wet weight (08.00 h). The number of m
ast cells per microscopic field ranged from 10.8+/-0.6 (16.00 h) to 14
.6+/-0.6 (12.00 h) in males and from 8.3+/-0.2 (04.00 h) to 14+/-0.4 (
12.00 h) in females. Chronobiologic analysis indicates that the levels
of all three variables follow a circadian pattern with a period of 12
h. Peak levels were noted at 07.36 h and 19.36 h for the blood histam
ine concentration, at 09.00 and 21.00 h for the tissue histamine conce
ntration, and at 11.00 and 23.00 h for the mast cell number. The consi
stent, consecutive relationship of these data supports the hypothesis
that thyroid mast cell number is conditioned by the blood histamine le
vel and thyroid histamine concentration.