The Effect of Cyproheptadine on Plasma Growth Hormone (GH) and on Somatostatin Response to GH-Releasing Hormone in Man

Summary

Cyproheptadine (CPH) - a putative serotonin antagonist - is known to inhibit growth hormone (GH) response to various pharmacological stimuli, as well as during sleep. To elucidate the possible site at which this drug takes effect, we examined plasma GH and somatostatin response to i. v. GHRH1-44 (1 μg/kg body wt.) before and after CPH treatment in 10 healthy volunteers. The oral administration of CPH (8-12 mg daily for 5 days; total dose 56 mg) significantly curbed GH response to GHRH as expressed in peak plasma GH values (32.0 ± 6.1 μg/l vs. 12.6 ± 3.2 μg/l; P < 0.01) and in integrated GH response area (2368 ± 517 μg × 1^-1 × 2 h vs. 744 ± 172 μg × 1^-1 × 2 h; P < 0.01). Plasma somatostatin levels did not change in response to GHRH.

Key words

Growth Hormone-Releasing Hormone - Growth Hormone-Cyproheptadine - Somatostatin