Enhanced plasma thyrotrophin response to thyrotrophin‐releasing hormone following oestradiol administration in man

Summary The plasma TSH response to 100 μg of TRH i.v. was studied in six normal women and in seven men before and after the administration of 10.0 mg of oestradiol valerate for 5 consecutive days. Before oestrogen treatment the females appeared more responsive than males. After treatment the response remained unchanged in females while appearing enhanced in males. Oestrogen treatment did not modify either the basal plasma TSH concentration or the serum thyroxine, the labelled tri‐iodothyronine uptake and the calculated free thyroxine index. It is concluded that oestrogens play a role in modulating the secretion of TSH from the human pituitary.