Studies on the poll glands of the one-humped camel in relation to reproductive activity. I. Seasonal morphological and histochemical changes.

The poll glands of the camel have been studied histologically and histochemically. An active gland, as observed between September and March, with a peak period in November and December, consists of sharply demarcated lobules separated by thin strands of connective tissue. Alveoli and proximal parts of excretory ducts are either lined with flat/simple cuboidal epithelium or with tall cells possessing distal protruding tips almost occluding the lumina; both segments, i.e. alveolus and proximal part of excretory duct, are therefore secretory. In the inactive gland there is an apparent increase in the interlobular stroma with massive deposition of collagenous fibres. The alveoli are lined with squamous to low columnar epithelium. The structural appearance in the castrate animal is essentially the same as that of the inactive gland except for its remarkable amount of interlobular tissue. Both delta 5-3 beta- and 17 beta-hydroxysteroid dehydrogenases have been demonstrated histochemically in the secretory portions of the gland. Their activity is restricted to the period between September and March and is comparatively highest during November and December. It is concluded that the morphological, enzymatic and secretory activities of the poll gland are correlated with testicular activity and rutting behaviour. It is suggested that the poll glands could be a source of sex pheromones.