Ultrastructural Changes in Parafollicular Cells of Indian Sheath-Tailed Bat, Taphozous longimanus (Hardwicke), during the Reproductive Cycle

The Indian sheath-tailed bat, Taphozous longimanus, at Nagpur (Maharashtra State) shows continuous asychronous breeding, exhibiting aseasonal polyoestry. The morphology of parafollicular cells (C) cells in the thyroid gland of bat was studied during different phases of reproductive cycle. During estrus, parafollicular cells are elongated, irregular or oval and larger than follicular cells. Golgi apparatus is inconspicuous. Mitochondria, with lamellar cristae, are sparse. Rough endoplasmic reticulum occurs in the form of short tubular profiles dotted with ribosomes. Membrane-bound granules of varying size and electron density are observed in the cytoplasm. During pregnancy most of the parafollicular cells are packed with granules. The Golgi complex is inconspicuous and the rough endoplasmic reticulum is sparse. Multivesicular bodies are observed. During lactation, parafollicular cells exhibit morphological characteristics suggesting low synthetic activity and storage of granules. These morphological findings are discussed in relation to previous findings in other bats and with physiological activities of bat during the different stages of reproduction.