Circadian pattern of prolactin secretion in children with growth hormone deficiency and congenital organic lesions in the hypothalamic-pituitary region.

OBJECTIVES: Prolactin (Prl) secretion in children manifests circadian rhythm. The aim of the study was to assess circadian Prl pattern in children with growth hormone deficiency (GHD) and congenital organic disorders in the hypothalamic-pituitary region (HPR).

MATERIAL AND METHODS: The analysis comprised 47 children (aged: 11.05+/-3.5 years) with GHD, divided (based on MRI) into subgroups: NORM (no disturbances in HPR); HP (pituitary hypoplasia) and PSIS (pituitary stalk interruption syndrome). The profile of circadian Prl secretion was determined, based on Prl measurements in serum every 3 hours during 24 hours. The macroscopic analysis of circadian Prl rhythm in particular groups was performed. The comparison group consists of 41 children (aged: 11.45+/-3.20 years) with idiopathic short stature (ISS).

RESULTS: In GHD-HP, diurnal and nocturnal Prl concentrations were low but with the dispersion between them and with normal rhythm in most of cases. In GHD-PSIS, diurnal and nocturnal Prl concentrations were on the same level and the rhythm was not observed in most of cases. No significant differences were found in Prl secretions and Prl rhythm between GHD-NORM and ISS. The rhythm of Prl secretion was disturbed in: 72.7% of children with GHD-PSIS, 23.5% - with GHD-HP, 10.5% with GHD-NORM and 7.3% with ISS, only.

CONCLUSIONS: Congenital organic lesions of HPR are associated with quantitative disorders and changes of the circadian pattern of Prl secretion. In children with GHD without organic lesions of HPR, the circadian rhythm of Prl secretion was not different from that with ISS.