Cosecretion of glycosylated prolactin and non-glycosylated prolactin from childhood to the end of puberty.

BACKGROUND: Glycosylated prolactin (G-PRL) is considered as the major post-translational modification of prolactin (PRL) showing reduced lactotropic and mitogenic activities compared to non-glycosylated prolactin (NG-PRL). AIM: To evaluate the evolution of G-PRL in normoprolactinemic children and adolescents and to analyze possible variations in glycosylated/total prolactin (T-PRL) ratios. METHODS: T-PRL, G-PRL and NG-PRL were evaluated in 111 healthy female and male children and adolescents (4.1-18 years), classified as group 1 (Tanner I), group 2 (Tanner II-III) and group 3 (Tanner IV-V). G-PRL and NG-PRL were identified by chromatography on concanavalin-A-Sepharose. RESULTS: G-PRL/T-PRL (median-range): females, group 1: 0.59 (0.17-0.77), group 2: 0.56 (0.31-0.78), group 3: 0.60 (0.38-0.79); males, group 1: 0.64 (0.39-0.80), group 2: 0.61 (0.24-0.79), group 3: 0.62 (0.35-0.90); the p value is not significant among the different groups in both genders. G-PRL/T-PRL ratios do not change when comparing low (first quartile) versus high (third quartile) T-PRL levels in the different groups. CONCLUSION: Our study would appear to support cosecretion of G-PRL and NG-PRL from childhood to the end of puberty. Such cosecretion would not be dependent on sex steroid levels. It is important to point out that puberty does not change the proportions of G-PRL and NG-PRL.

Controversies in the evolution of paediatric-adolescent varicocele: clinical, biochemical and histological studies.

OBJECTIVE: To study hormonal and histological parameters of paediatric-adolescent varicocele in order to know certain aspects of its natural history, in an attempt to find prognostic markers of testicular damage. DESIGN AND METHODS: In a prospective cross-sectional study, we evaluated 93 children and adolescents with left unilateral varicocele and 29 healthy males as control group. All of them were classified according to Tanner stage. Scrotal Doppler in both testes and GnRH and human chorionic gonadotrophin (hCG) tests were performed in all subjects. Surgery was performed in 28 patients and homolateral testicular biopsy in 18. RESULTS: Hormonal measurements of patients with varicocele were compared with a control group for each Tanner stage. Testicular biopsy specimens were analysed by light and electron microscopy. We only observed statistical differences in Tanner III patients in basal FSH (median and range) controls=1.70 (1.10-3.70) IU/l vs varicocele=4.20 (1.00-7.50) IU/l, P<0.05 and in Tanner IV patients in LH post-GnRH: controls=11.0 (7.50-15.0) IU/l vs varicocele=18.0 (5.10-29.0) IU/l, P<0.05 and in testosterone post-hCG: controls=9.50 (7.7-10.0) ng/ml vs varicocele=12.0 (6.2-23.0) ng/ml, P<0.01. No correlation was found between the various clinical grades of varicocele and hormonal measurements for each Tanner stage. No statistically significant differences were found between pre- and post-operative hormonal findings, either in basal levels or in maximal responses. On the other hand, no morphological abnormalities were observed by electron microscopy in germ cells, tubular wall and interstice. CONCLUSIONS: There appears to be no reliable biochemical marker in children and adolescents that may predict impaired testicular function. A significant size discrepancy between both testes, testicular pain and a hyperresponse to GnRH stimulation should continue to be, for the time being, the indications for surgery.

Immunoradiometric assay of thyrotropin during the first six months of life.

The aim of this preliminary study was to assess variation in thyrotropin (thyroid-stimulating hormone; TSH) levels using an immunoradiometric assay during the first 6 months of life of normal infants. One hundred and five normal newborns (59 females, 46 males) were evaluated for TSH, triiodothyronine and thyroxine at 48 h of life, and TSH was additionally determined at 15 days (n = 42), 30 days (n = 38), 60 days (n = 24), 90 days (n = 28), and 180 days (n = 30). Complete determinations during the total period of the study were obtained in 17 infants. Samples corresponding to the 48-hour period did not exhibit a normal distribution. In this group, percentile 3 corresponded to 0.9 mU/l, the median to 4.2 mU/l and percentile 97 to 17.7 mU/l. Levels of TSH similar to those of the normal adult population were reached between 30 and 60 days of life. Nevertheless, TSH levels of some of the children remained at higher values for a longer period. In summary, our results suggest that high TSH levels might not always indicate an underlying pathology. A critical evaluation of the normality criteria could avoid unnecessary studies and treatments.