Neonatal ovine adrenal cortical and medullary cell H+ responses to ACTH and prostaglandin E₂

The microphysiometric technique was used to evaluate 1- and 3-day-old lamb adrenal gland H+ production in response to ACTH or PGE₂. ACTH stimulated cortical, but not medullary H+ production; maximal H+ by combined cortical and medullary cells was greater than by cortical cells alone (p<0.05). In contrast, the magnitude of the H+ response to PGE₂ was greater with medullary than with cortical cells alone or with cortical and medullary cells combined (p < 0.05). The H+ response to ACTH was greater in 3-day-old compared to 1-day-old lambs while the potency of PGE₂ was not different at the ages studied. We conclude that in neonatal sheep: (1) ACTH and PGE₂ are potentially important in adrenal regulation, and (2) paracrine communication appears to be functioning as has been shown for adults.