SEASONAL-CHANGES IN THE RENAL MORPHOMETRY OF ANTECHINUS-STUARTII (MARSUPIALIA, DASYURIDAE)

The renal morphology of Antechinus stuartii was examined in males and females in February, May, July and August. Kidney mass was higher in m ales than females, although the reverse was true when adjusted for bod y mass. The predicted kidney mass and kidney size calculated from allo metric equations were significantly larger than the actual values in m ales from August, although at other times and for females these values were not different. Relative medullary thickness, percentage medullar y thickness and medullary thickness were not different between seasons or sexes. Both superficial and juxtamedullary glomerular volumes incr eased in July and August in males and this coincided with a reduction in glomerular number per mm(2) of cortex. In general, tubular diameter s increased in males in July and August, but not in females. The same was true of cellular volumes from the same sections of the nephron. Th e renal morphological changes in the males correlate with the life his tory and endocrine changes of A. stuartii.