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Impairment of platelet function by growth-hormone release-inhibiting hormone

G M Besser, A M Paxton, S A Johnson

    Lancet (London, England)
    |May 24, 1975
    PubMed

    Insights

    Synthetic cyclic growth-hormone release-inhibiting hormone (G.H.-R.I.H.) infusions temporarily impaired platelet aggregation in healthy men. While G.H.-R.I.H. did not affect clotting times, caution is advised for prolonged use due to potential side effects.

    Area of Science:

    • Endocrinology
    • Hematology
    • Pharmacology

    Background:

    • Growth-hormone release-inhibiting hormone (G.H.-R.I.H.) is a synthetic peptide hormone.
    • Platelet aggregation plays a crucial role in hemostasis and thrombosis.
    • Previous studies suggested potential effects of G.H.-R.I.H. on platelet function in animal models.

    Purpose of the Study:

    • To investigate the effects of synthetic cyclic G.H.-R.I.H. on platelet aggregation and other hemostatic parameters in healthy human subjects.
    • To assess the duration of G.H.-R.I.H.'s impact on platelet function.
    • To evaluate potential side effects associated with G.H.-R.I.H. infusion.

    Main Methods:

    • Four healthy male volunteers received 6-hour infusions of synthetic cyclic G.H.-R.I.H.
    • Platelet aggregation, platelet counts, prothrombin-time, partial thromboplastin-time, fibrinogen titres, and fibrinogen-degradation products were measured.
    • In vitro incubation of G.H.-R.I.H. with blood was performed to assess direct effects on platelet aggregation.
    • Adverse events were monitored during and after the infusions.

    Main Results:

    • Synthetic cyclic G.H.-R.I.H. impaired platelet aggregation in all subjects during the 6-hour infusion.
    • The anti-aggregatory effect persisted for over 24 hours in three out of four subjects.
    • No significant changes were observed in platelet counts during infusion, but a slight increase occurred 18 hours post-infusion.
    • Coagulation parameters (prothrombin-time, PTT, fibrinogen, FDPs) remained unchanged.
    • In vitro incubation did not affect platelet aggregation, suggesting an indirect mechanism.
    • Common side effects included abdominal pain, dizziness, and diarrhea in three subjects.

    Conclusions:

    • Synthetic cyclic G.H.-R.I.H. significantly impairs platelet aggregation in humans, with prolonged effects.
    • G.H.-R.I.H. does not appear to affect standard coagulation tests or platelet counts acutely.
    • Caution is warranted for extended G.H.-R.I.H. use due to potential side effects and unknown long-term toxicity.
    • Further research is needed to elucidate the precise mechanism and long-term safety profile of G.H.-R.I.H.

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