SEX-HORMONAL REGULATION OF 20.5 AND 24KDA MAJOR MALE-SPECIFIC PROTEINS IN SYRIAN-HAMSTER SUBMANDIBULAR-GLAND

Examination of SDS-PAGE protein profiles of adult hamster submandibula r glands revealed a marked sexual dimorphism in levels of 20.5 and 24 kDa proteins. These proteins, together apparently constituting 40% of soluble proteins, were present in intact and castrated males but not i n females. This sexual dimorphism was also confirmed in two-dimensiona l gels which revealed that the protein at 24 kDa was heterogenous and consisted of at least four species. In females, ovariectomy induced th e 20.5 and 24 kDa proteins to male levels. Estrogen administration to gonadectomized hamsters of either sex or to intact males obliterated t hese proteins. Whereas androgens had no effect in males, they markedly inhibited these proteins in ovariectomized females. Androgens were le ss potent than estrogens in this regard. Progesterone or dexamethasone had no effect on these proteins. Only male saliva contained 20.5 and 24 kDa major proteins. These submandibular male-specific proteins are useful markers to study the hormonal regulation of this gland, and the y provide a model system to study how both androgens and estrogens med iate inhibition of protein synthesis. The possible functions of these submandibular male-specific proteins are discussed. Copyright (C) 1996 Elsevier Science Ltd.