Treatment of rats with GnRH antagonist impairs reproductive status but does not affect <i>Mt1</i> expression.

<p>Male Wistar rats were given a daily i.p. injection of the GnRH antagonist cetrorelix (100 µg/day) or saline control for 4 weeks. (A) Serum LH was measured by ELISA. (B–C) Testis morphology was assessed by (B) paired testis weight and (C) histological analysis of tissue sections using hematoxylin and eosin staining. Scale bar = 25 µm (D–E) Brain and pituitary tissue from saline and cetrorelix-treated rats was dissected with the pituitary stalk intact, frozen on dry ice and stored at −80°C. Twenty micron sagittal sections were cut and <i>Mt1</i> mRNA expression determined by in situ hybridisation histochemistry. (D) Representative autoradiographs. In both treatment groups, strong pituitary expression was observed in the pars tuberalis and along the rostral extent of the ventral pars distalis; weaker expression was observed throughout the rest of the pars distalis. (E) Quantification of <i>Mt1</i> expression by densitometry. *** p<0.001 saline vs cetrorelix group (unpaired t-test). Sal: saline-treated; Cet: cetrorelix-treated.