Evaluation of pituitary functional periodicity by harmonic analysis. I) Circadian somatotropin secretion in acromegaly

: PRL levels over 24 hours have been studied in 9 acromegalic patients (4 men and 4 women). Hormone levels were found significantly higher than age and sex matched normal subjects in 4 cases (2 males and 2 females). PRL and STH levels were significantly correlated in men, but not in women. A 24-hour periodicity of PRL secretion was found in 4 cases, however in 2 of them the phase was anticipated in respect to the control group. In 4 of the remaining subjects the hormone secretion is made up by a succession of episodes with higher frequency than in the control group. Only in one case no significant periodicity of secretion was observed.