title: Age-dependent decrease of beta-adrenoceptor density in the submandibular glands of mice and its modulation by the thymus.
abstract: Beta-adrenergic receptors were characterized in submandibular glands of ageing mice and old mice grafted with a neonatal thymus. No statistically significant changes of receptor affinity were found in the animal models investigated. On the contrary, receptor density showed a progressive decrease with advancing age. The age-related decrease has been found partially corrected in thymus-grafted old animals, which show a statistically significant recovery of receptor density when compared to their untreated littermates. Receptor modulation can be responsible for the age-related impairment and the thymus-dependent correction of beta-adrenergic responsiveness of submandibular glands previously observed in vivo. Hormonal balance and thyroid hormones, in particular, are suggested as being involved in the age- and thymus-dependent regulation of receptor density. In the accompanying Appendix, we describe the mathematical method used to calculate both specific and nonspecific binding from total binding data.
mesh_terms: D000375:Aging; D000818:Animals; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D011941:Receptors, Adrenergic / Q000032:analysis*; D011943:Receptors, Adrenergic, beta / Q000032:analysis*; D013363:Submandibular Gland / Q000378:metabolism*; D013950:Thymus Gland / Q000502:physiology* / Q000637:transplantation
chemical_list: D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta