The Influence of 17β-oestradiol on Corticotrophin-releasing Hormone Induced Suppression of Luteinising Hormone Pulses and the Role of CRH in Hypoglycaemic Stress-induced Suppression of Pulsatile LH Secretion in the Female Rat

Abstract

Corticotrophin-releasing hormone (CRH) released during stress has been implicated in the disruption of the reproductive neuroendocrine axis, and 17β-oestradiol (E₂) has been shown to enhance stress-induced suppression of pulsatile gonadotrophin-releasing hormone (GnRH) and luteinising hormone (LH) release. The aims of the present study were to examine the role of CRH in hypoglycaemic stress-induced suppression of LH pulses, and to investigate the influence of E₂ on the inhibitory effect of CRH on pulsatile LH secretion in the female rat. Suppression of LH pulses by insulin-induced hypoglycaemic (IIH) stress was completely prevented by intracerebroventricular (icv) administration of a CRH antagonist. Central administration of CRH (5 μg) resulted in an interruption of LH pulses in E₂ treated animals, but had little or no effect in the absence of this gonadal steroid. These results provide evidence of a pivotal role for CRH in mediating the suppressive effect of IIH stress on pulsatile LH secretion in the female rat, and highlight a sensitising role for E₂ in CRH-induced suppression of LH pulses.

• CRH
• CRH antagonist
• Hypoglycaemia
• LH pulses
• Oestradiol
• Stress