THYROID ACTIVITY AND TSH LEVEL IN PITUITARY-GLAND AND BLOOD-SERUM IN RESPONSE TO CLOMID, SEXOVID AND PROSTAGLANDINS TREATMENT IN HETEROPNEUSTES-FOSSILIS (BLOCH)
Thyroid activity, pituitary and serum thyrotrophic potency in response to the administration of clomid, sexovid, PG[prostaglandin]E1 and PGF2.alpha., were studied in H. fossilis. Heightened thyroidal activity and CR (conversion ratio of PB 131I in blood serum in relation to total serum 131I uptake) were noticed a week after clomid (150 .mu.g/fish per day) and sexovid (150 .mu.g/fish per day) treatment. Clomid and sexovid also elevated the serum thyrotrophic potency, although pituitary TSH level was unaffected. Clomid and sexovid either act via the hypothalamus or directly over the pituitary to increase TSH secretion followed by increased thyroid activity. PGE1 and PGF2.alpha. (100 .mu.g/fish per day, each) administration increased thyroidal 131I uptake but failed to stimulate hormone output from thyroid gland. Increased TSH level in blood and decreased level of TSH in the pituitary was observed in response to the PG. PGE1 and PGF2.alpha. seem to inhibit thyroid hormone secretion like anti-thyroid drugs triggering the release of TSH into blood.