Bidder's Organ

Bidder's Organ, an organ of male toads, located above the testes, beneath the fatty body. In one species, Bufo vulgaris, it also exists in females. In structure, the Bidder's organ resembles an ovary, in which the oocytes reach the synapsis stage (see), after which they degenerate. It develops from the upper part of the common rudiment of the sex gland; initially it grows faster and reaches a larger size than the lower part—the future sex gland. Previously, the Bidder's organ was considered a rudimentary organ, but recent research has shown the great importance of this organ from both a physiological point of view and for solving the problem of sex transformation and the role of so-called interstitial cells. Accordingly, the Bidder's organ is a secretory gland and undergoes the same cyclic changes as the puberty gland of mammals. It decreases greatly in volume in early spring and reaches maximum development by autumn. Experiments with removal of the testes have shown that the Bidder's organ secretes hormones that maintain all essential secondary characteristics of one sex or the other, while it completely lacks the so-called interstitial cells, which play such an important role in the formation of secondary sexual characteristics in mammals. After removal of the testes, with abundant feeding of the operated animal with lecithin and lipoids, with interruptions for fasting, the Bidder's organ transforms into a properly functioning ovary with the transformation of the animal into a complete female: the masculinus uterus turns into oviducts, the secondary sexual characteristics of the male disappear, the head becomes wider, the big toes become more delicate, the ability to emit sounds during the sexual period disappears; complete transformation of the male into a female occurs, approximately, within two years.