Distribution of thyroid follicles and nerves in the kidney of a teleost, Clarias batrachus (Linn.).

The kidney of Clarias batrachus is distinguished morphologically into head, trunk and mesonephric lobes. All parts of the kidney are provided with heterotopic thyroid follicles. The study of serial sections indicates that they are migrated from Pharyngeal region along the blood vessels. They are present in the form of clusters at the opening of the blood vessels in these parts. Presence of nerves in close proximity to the heterotopic thyroid follicles indicates that nerves may have some control on the renal thyroid follicles. The presence of nerve plexuses in parenchyma of trunk kidney and in the afferent and efferent vessels has been recorded. The prolific innervation suggests that nerves have definite control over the regulation of blood flow in the trunk kidney.