The authors examined the concentration of thyrotropic hormone (TSH) and prolactin (PRL) before and after stimulation with synthetic thyroliberine (0.2 mg TRH i.v.) in a group of 72 women with primary hypothyroidism (mean age 45 years, range 17 - 69 years) and l2 controls (mean age 35 years, range 17-49 years). According to the total thyroxin concentrations (TT4) and TSH they divided the group into three smaller subgroups: developed primary hypothyroidism (n = 8, mean age 50 years, TT4 < 65 nmol/l, basal TSH concentration > 15.0 mIU/l nmol/l), subclinical hypothyro- idism, severe grade (n = 23, mean age 36 years, TT4 > 65 nmol/l, basal TSH concentration < 4.5 mIU/l),subclinical hypothyroidism mild degree (n = 39, mean age 42 years, TT4 > 65 nmol/l, basal TSH concentration < 4.5 mIU/l, TSH after TRH stimulation > 25 mIU/l). Mean basal PRL concentrations were in all three patient groups significantly higher than in the control group (P < 0.01) but mutually they did not differ significantly. Poststimulation PRL concentrations were also significantly higher than in controls however the values in developed hypothyroidism were significantly higher than in subclinical patients. No correlation was found between TSH and PRL concentrations.

        Key words: Prolactin (PRL) - Thyrotropic hormone (TSH) - Thyroliberin (TRH)- Primary hypothy- roidism - Subclinical Hypothyroidism