Gender, Sex Hormones, and Secretagogues Influence Growth Hormone Recovery in Older Adults

Growth hormone (GH) is a crucial peptide hormone involved in metabolism, body composition, and overall well-being. As individuals age, GH levels naturally decline, a phenomenon known as somatopause, which can contribute to age-related health issues. The body's intricate feedback mechanisms tightly regulate GH secretion, but how these mechanisms recover after suppression, particularly in older populations, is not fully understood. This study addresses how gender, sex-steroid hormones, and specific GH secretagogues affect the recovery of endogenous GH secretion after exogenous GH-induced feedback in older men and women.

The study revealed significant gender-specific differences in the recovery of growth hormone secretion. Women demonstrated significantly faster recovery of GH pulse amplitude, achieving 75% of their baseline levels by 6 hours post-secretagogue, compared to men who reached only 45% by the same time (p<0.001). Estrogen levels in women positively correlated with the rate of GH recovery (r=0.72, p<0.005), with women in the highest estrogen quartile showing a 2.1-fold faster recovery. Conversely, in men, higher free testosterone levels were associated with a 1.8-fold slower recovery of GH pulse frequency (p<0.01). Furthermore, GHRH administration resulted in a 35% higher peak GH response compared to GHRP-2 in older men (p<0.001), while in women, the difference was only 10% and not statistically significant. > Women exhibit a more robust and rapid recovery of endogenous growth hormone secretion following exogenous suppression compared to men, with sex-steroid levels playing a critical modulatory role.