LEAP‐2/ghrelin interplay in adult growth hormone deficiency: Cause or consequence? A pilot study

Ghrelin and its endogenous antagonist liver‐expressed antimicrobial peptide‐2 (LEAP‐2) are involved in GH secretion and glucose/lipids metabolism. LEAP‐2 expression in conditions of metabolic impairment may be upregulated, usually pairing with a concomitant reduction in ghrelin secretion. Adult growth hormone deficiency (aGHD) is characterized by insulin resistance, weight gain, and increased fat mass. Therefore, the primary endpoint of this cross‐sectional observational pilot study was to compare circulating LEAP‐2 and ghrelin levels in aGHD and healthy controls. Thirty patients were included in the study. Group A included adult GHD: 15 patients, 8 females, and 7 males. Median and interquartile range age of the group was 53 (41–57) years, while BMI was 27.1 (25–35) kg/m(2). Group B was formed by 15 healthy controls (10 females and 5 males). Median and interquartile range age was 47 (36–57) years, while BMI 22.9 (20.8–33.1) kg/m(2). They were evaluated for serum glucose and insulin, HOMA‐index, QUICKI‐index, total/LDL/HDL cholesterol, triglycerides, IGF‐1, ghrelin, and LEAP‐2. Ghrelin levels in the aGHD group were significantly lower than in healthy controls. In contrast, LEAP‐2 showed a trend toward higher levels, although the differences were not significant. However, the LEAP‐2/Ghrelin ratio was significantly higher in aGHD. No significant correlations between ghrelin and LEAP‐2 with BMI and HOMA index were found in aGHD population. However, a significant inverse correlation (r (2) = 0.15, p = .047) between BMI and ghrelin was evidenced when considering the whole population. Taken together, these results may suggest a body adaptation to a metabolic scenario typical of aGHD. The decrease in ghrelin production could prevent further weight gain and fat mass increase, although losing its secretagogue effect.