Dolichol (D) levels increase dramatically in older tissue. An understanding of the exchangeability of D between tissues may be essential in order to understand the mechanism of the abnormal accumulation associated with aging. The question was investigated by the use of organ transplantation. D-poor hearts donated by 3-mon-old and D-rich by 22-mon-old male Lewis rats were transplanted heterotopically in 3-mon-old syngenic recipients, whose peripheral tissues and liver were poor in D. Native and transplanted hearts were taken 7 and 21 d after surgery. Native hearts of 3-mon- and 22-mon-old male Lewis rats served as control. D concentration and quantity were higher in older than in younger native hearts as expected. In the transplanted hearts, the quantity of D was unchanged, irrespective of the age of the donor and of the time of transplantation, whereas D concentration increased because of the remarkable disuse atrophy. No changes in D were observed in recipients' tissues. It is concluded that dolichol is not redistributed via circulation from the transplanted heart to the tissues and liver of the younger recipient.