Pituitary thyroid function and prolactin release following intravenous administration of TRH and pyroglutamyl-histidyl-prolyl-β alanine amide to healthy volunteers.

The synthetic oligopeptide pyroglutamyl-histidyl-prolyl-β-alanine amide, structurally related to thyrotrophin releasing hormone (TRH), has been investigated in healthy male volunteers for its effect on pituitary thyroid function and on serum prolactin levels. In an open randomised 2-way crossover study the peptide has been compared with TRH on an equal dose basis following intravenous administration at 4 dose levels. The synthetic material had significantly lower thyrotrophin (TSH)-releasing activity than TRH while the prolactin releasing potencies of the 2 peptides were about equal.