Razi Journal of Medical Sciences

This study was designed to evaluate specific effect of thyroid hormone on growth and development of reproductive organs in male rats, during one year period from 1994-1995 in the Dept of physiology M.S.U. of Tehran.

In this investigation the early hypothyroidism was induced with the use of PTU and the developmental changes in endocrine and nonendocrine organs (kidney and spleen) were studied.

The test group animals were those who recieved PTU, and the second group were the control animals.

During different periods after birth serum levels of testosterone hormones, testicular total protein synthesis, body weight and the ratio of spleen and kidney weights to total body weights were measured and compared with control groups.

In conclusion, in test group weight increase rate up to 60th day of life were less than the control and the differences were statistically significant (p

PTU effects on non endocrine system, weight increases (kidney and spleen) were not significant. Testicular weight up to the 60th day in the test group showed a significant difference when compared to controls in the test animals.

The total testicular protein synthesis and testosterone secretion were less than controls, too.

We conclude that the thyroid hormones play an effective role in regulation and control of testis and their absence cause significant changes in gonads, hypophysis and probably hypothalamus secretory patterns, with the lag in onset of puberty, in male rats.