Seasonal variations in the ultrastructure and production of androgen-dependent proteins in the seminal vesicles of a Saharian rodent (Psammomys obesus)

Abstract

The effects of seasonal variations and experimental deprivation and substitution of androgen in the seminal vesicles of the Saharian rodent Psammomys obesus were investigated. Cytological studies showed that, during the breeding season, epithelial cells had large amounts of rough endoplasmic reticulum (RER) and substantial apocrine secretion. During the non-breeding season, RER cisternae were no longer expanded and apocrine secretion was rare. Castration during the breeding season was followed by regression of the RER and the disappearance of apocrine secretion. Treating castrated animals and animals in the non-breeding season with testosterone for 15 days caused reactivation. Eight major proteins with molecular weights of 120, 78, 67, 41, 37, 34, 21 and 14.4 kDa were present in homogenates during the breeding season; six (92, 41, 36, 35, 21 and 14.4 kDa) were found in seminal vesicle secretions. During the non-breeding season, the very large amounts of the 21 kDa protein were greatly reduced; conversely the 45 kDa protein increased. Electrophoretic patterns of homogenates from animals castrated during the breeding season showed eight proteins differentially induced (37, 34, 21 and 18 kDa) or repressed (67, 45, 38 and 35 kDa) by testosterone, of which the 21 kDa protein decreased most dramatically after castration. The effects of castration were reversed by the administration of testosterone. During the non-breeding season, the synthesis of the four induced proteins was stimulated by testosterone treatment; conversely that of the 45 kDa protein was suppressed.