What are analogues and homologous

Mechanisms of action of gonadotropin-releasing hormone and its analogues

On the subject

The hypothalamic decapeptide gonadotropin releasing hormone (GnRH) binds to specific membrane receptors of the gonadotropic anterior pituitary cell and causes the release of gonadotropins. The activation of the receptors leads to the hydrolysis of membrane phospholipids with the release of inositol triphosphate (IP3) and diacylglycerol (DG). Both act as a "second messenger". IP3 leads to the mobilization of calcium (approx2 + ) from intracellular stores, while DG activates protein kinase C (PKC). The increase in the intracellular Ca2 + Concentration ([approx2 + ] i) is the most important signal for the initiation of gonadotropin secretion. PKC plays a role both in exocytosis and in the new synthesis of gonadotropins. The effect of GnRH on gonadotropin secretion is influenced to a considerable extent by ovarian steroids. Inhibitory and stimulatory effects of estradiol and progesterone can be mediated by modulating signal transduction mechanisms. GnRH analogs also bind to the GnRH receptor; GnRH agonists (GnRHag), like natural GnRH, initially cause the release of gonadotropins; later, homologous desensitization leads to a suppression of gonadotropin secretion. In contrast, the application of GnRH antagonists (GnRHant) immediately leads to a suppression of gonadotropin secretion. This effect is based on a competitive inhibition of the binding of GnRH to the pituitary receptor. The lack of an initial increase in gonadotropin secretion gives the GnRHant a certain superiority in terms of the therapeutic goal. This makes them the drugs of choice for certain indications.

Access options

Buy single article

Instant access to the full article PDF.

34,95 €

Tax calculation will be finalized during checkout.

Subscribe to journal

Immediate online access to all issues from 2019. Subscription will auto renew annually.

303,74 €

Tax calculation will be finalized during checkout.

Author information

Affiliations

  1. Clinic for Gynecology and Obstetrics, Medical University of Lübeck

    O. Ortmann & K. Diedrich

  2. Women's Clinic, Georg-August University of Göttingen

    G. Emons

About this article

Cite this article

Ortmann, O., Emons, G. & Diedrich, K. Mechanisms of action of gonadotropin-releasing hormone and its analogues. gynecologist31, 1051-1056 (1998). https://doi.org/10.1007/s001290050374

Download citation