Expression patterns of parathyroid hormone-related peptide (PTHrP) and parathyroid hormone receptor type 1 (PTHR1) during human development are suggestive of roles specific for each gene that are not mediated through the PTHrP/PTHR1 paracrine signaling pathway.

Close temporal and spatial relationships between Pthrp and Pthr1 gene expression are reported during fetal life in rats, suggestive of a developmental role via a paracrine signaling pathway. In agreement, disruption of this signaling pathway is associated with developmental defects, as documented in mice and humans. Surprisingly, however, only few organs are affected. We report here PTHrP and PTHR1 gene expression during human embryo-fetal development. We describe three patterns: in some organs, both genes are active ('hand-in-glove' fashion), while in others either PTHrP or PTHR1 transcripts are detected. In addition, in some tissues, expression of PTHrP or PTHR1 genes is transient. Abnormal development has been documented only for organs expressing both genes. The patterns that we observe are compatible with specific roles for each gene not mediated through the PTHrP/PTHR1 signaling pathway.