Disorders of gonadotrophin secretion.

Disorders of gonadotrophin secretion.

In recent years, particularly since the advent ofradioimmunoassay, the regulation of pituitary gonadotrophin secretion has been extensively studied in man and in animals (Greep et al., 1976). I shall not comprehensively catalogue the different diseases and syndrome complexes associated with disordered gonadotrophin secretion. These are systematically covered in several textbooks and reviews (Lo...

Intracellular mechanisms triggering gonadotrophin secretion.

The recently cloned GnRH receptor, a G-protein coupled receptor that spans the membrane seven times, plays a central role in the maintenance of normal reproductive events. In pituitary gonadotrophs, activation of the GnRH receptor stimulates a concert of intracellular signalling pathways. Phospholipase C stimulation generates inositol 1,4,5 trisphosphate and diacylglycerol, which release calciu...

The role of pituitary gonadotrophin-releasing hormone receptors in the physiological regulation of gonadotrophin secretion.

Effects of changing gonadotrophin-releasing hormone pulse frequency on gonadotrophin secretion in men.

To investigate the effects of alterations in GnRH pulse frequency on gonadotrophin secretion, we administered low dose GnRH pulses (25 ng/kg) at hourly or 2-hourly frequencies to eight normal men. All subjects received GnRH pulses i.v. every 2 h for 88 h. Following this, exogenous GnRH was discontinued in four normal men (Group A, GnRH withdrawal), and the frequency of GnRH injections was incre...

Pulsatile gonadotrophin secretion in women with polycystic ovary syndrome after gonadotrophin-releasing hormone agonist treatment.

In polycystic ovary syndrome (PCOS), increased luteinizing hormone (LH) pulse frequency has been attributed to either the hypothalamic gonadotrophin-releasing hormone (GnRH) pulse generator or ovarian oestrogen feedback. To address this issue, a detailed examination of pulsatile LH secretion was undertaken during recovery from GnRH agonist (GnRHa) suppression. Each of six women with PCOS and si...