Parathyroid hormone-related peptide (PTHrP) is found in very high concentrations in the milk of various mammals. However, little is known about its physiological role in this fluid. To obtain detailed profiles of PTHrP in milk, we measured the concentrations of PTHrP in human milk by two different region-specific assays, PTHrP(1-87) (N-PTHrP) and PTHrP(109-141) (C-PTHrP). We also examined the correlations between PTHrP and Ca concentrations in milk as well as the correlations between PTHrP and secreted milk volume. The levels of N-PTHrP and C-PTHrP were relatively low after delivery and gradually increased to 13.87 +/- 2.40 nmol/l (mean +/- S.E.M.) and 56.39 +/- 11.31 nmol/l respectively on the 10th day postpartum. N-PTHrP concentration remained steady until the 6th month postpartum when weaning starts, at which point it decreased slightly. C-PTHrP levels changed in a similar way to N-PTHrP levels but were 2- to 5-fold higher. Milk Ca concentration, and content, correlated with C-PTHrP concentration, and content (r = 0.422 and r = 0.769 respectively; P < 0.0001) but not with N-PTHrP. N-PTHrP concentration in the milk samples on the 4th day postpartum correlated with the volume of milk secreted during the 24 h before the samples were taken (r = 0.524, P < 0.01), but C-PTHrP concentration did not. These results suggest that PTHrP in human milk may play some role in the maintenance of lactation through the N-terminal region and in promoting Ca transfer into milk via the C-terminal region.
Purpose : It is essential to determine normative data of testicular size and penile length in newborn infants in order to assess the development during the fetal period. In this study, we evaluated testicular volumes using ultrasonography and also measured penile lengths in Japanese newborn infants. We also examined the associations of the development of these organs with factors including placental weight and anthropometric data. Methods : One hundred and fifteen full-term male newborn infants were recruited for this study. Testicular size was measured by ultrasonography. Results : Mean testicular volumes were 187.4 mm 3 in the right testis and 185.4 mm 3 in the left testis, and there was no significant difference between the right and left testicular volumes. Right and left testicular volumes showed positive and significant correlations with body lengths and weights. Testicular volumes in the right and left sides were not significantly associated with penile lengths. In 4 groups according to gestational weeks, testicular volume increased significantly with advance of gestational weeks in the left testis. Conclusion : We determined testicular volumes using ultrasonography in Japanese newborn infants. We believe that the results for newborn infants provide important information for assessment of the development of fetal testicular volume.
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