At approximately day 1

Epithelial cells within the crypts at the base of the small and large intestines show immunostaining for human growth hormone receptors.

Duration: 1 week

Reference [PubMed Link]

Simard M, Manthos H, Giaid A, Lefebvre Y, Goodyer CG. 1996 Aug. Ontogeny of growth hormone receptors in human tissues: an immunohistochemical study. J Clin Endocrinol Metab 81(8):3097-102.