THE NUMBER OF CATECHOLAMINE STORAGE GRANULES IN ADRENAL MEDULLA
HARVARD MEDICAL SCHOOL BOSTON MA
Pagination or Media Count:
A method is described for counting the catecholamine-containing heavy granules of adrenal glands. There are 5.0 0.8 S. E. x 10 to the 12th power granulesgram wet weight of fowl adrenal gland. Individual heavy granules contain about 8 million molecules of catecholamines 1.4 x 10 to the 17th power mole. Reference to published electron microphotographs of adrenal medulla cells allows estimation of the average volume of heavy granules and calculation of the intragranular concentration of catecholamines. The latter probably exceeds 0.5 M. Therefore, unless catecholamines are chemically bound to some polyvalent constituent within the heavy granules, their osmotic activity would be expected to be greater than is consistent with the maintenance of granule integrity.