Evidence for alpha-adrenergic receptors mediated TSH release in men

In order to elucidate the role of the adrenergic nervous system in the mechanism of TSH release in men the effects of alpha- and beta-receptors blocking agents were studied in 11 healthy volunteers. Phentolamine administered iv as a bolus injection in a dose of 10 mg, significantly lowered the TSH release in basal condition and in response to TRH stimulation. However, propranolol in a dose of 0.1 mg/kg administered in the same fashion as phentolamine had no effect on the TSH secretion. The results obtained suggest that the alpha-receptors of the adrenergic system are involved in the physiological mechanism which stimulates TSH release in men.