The morphology of the endocrine system in congenitally athymic (nude) mice.

: The endocrine system (adenohypophysis, thyroid, adrenals, ovaries, testes) and the submandibulary salivary gland of both female and male congenitally athymic (nu/nu) B10LP mice at various ages post partum (2, 4, 6, 8 and 12 wks) were studied morphologically and compared with their heterozygous thymus-bearing (+/nu) littermates. The animals were held under conventional conditions. The adenohypophysis of male nu/nu mice showed a decrease in size of the acidophilic cells. In the thyroid glands a slight hyperactivity of the follicles was seen in both female and male nu/nu mice in comparison with the +/nu mice. No changes were observed in the adrenals. The ovaries of the nu/nu females showed degeneration in the follicles while the corpora lutea were absent or, if present, degenerated. In the testes of nu/nu mice only a slight retardation in spermatogenesis was seen at wk 4. In the submandibular salivary glands of the nu/nu males the normal sex-dependent presence of well-developed tubular structures was absent from wk 4 onwards. The results were compared with those described in the literature for athymic mice with another genetic background and for thymectomised mice. It was concluded that alterations in immunological reactivity in athymic mice are not necessarily due to changes in the immune system, but may also be dependent on changes in endocrine function.