Fig. 5.

Comparison of gowth hormone (GH) release in response to challenge in delta-like 1 homologue (Dlk1)-null and wild-type mice. Jugular catheters were inserted into anaesthetised male wild-type and Dlk1-null mutant mice, and blood samples taken before and 5 and 15 min after i.v. injection of 500 ng of growth hormone-releasing hexapeptide (GHRP-6). Ninety minutes later, blood samples were taken before and 5 and 15 min after i.v. injection of 100 ng growth hormone-releasing hormone (GHRH). Plasma was isolated and assayed for circulating GH by radioimmunoassay. Data are shown as the mean ± SEM of six to eight mice. *P < 0.05 Dlk1-null versus wild-type littermates.