Seasonal histochemistry of the renal sexual segment in male common water snakes, Nerodia sipedon (L.)

Abstract

The histochemistry of the renal sexual segment of male common water snakes, Nerodia sipedon (L.), was studied throughout the active season. This segment is hypertrophied in early spring and late autumn, coinciding with peaks in plasma androgen levels. Secretory granules, present in epithelial cells lining the kidney tubule lumen of the sexual segment, are most evident at these times. Granules stain most intensely with periodic acid – Schiff, Sudan black B, and Oil red O from snakes collected in early spring and nearly as strongly from snakes collected in late autumn. Mercuric bromphenol blue and the Millon reaction stain granules most intensely from autumn captured animals. Granules from midsummer animals stained weakly with all of the above stains. It is suggested that the renal sex segment secretion plays a dual role, one of sperm transport and capacitation (final sperm maturation in the female reproductive tract) in autumn and another related to sexual behavior in the spring.