To elucidate the temporal relationship between LHRH and LH gene expression in response to testosterone (T), LHRH mRNA in the hypothalamus, and α and LH β mRNA in the anterior pituitary were simultaneously determined. After Silastic capsules containing T were implanted subcutaneously to castrated (2 weeks) adult rats, LHRH, α and LH β mRNA levels were determined by RNA-blot hybridization assay and hypothalamic LHRH content and serum LH levels were measured by radioimmunoassays. T implant to castrated rats decreased α and LH β mRNA levels in time- and dose-dependent manners, which were accompanied by parallel change in serum LH levels. On the other hand, T implant did not significantly alter LHRH mRNA level, which was discordant with changes in α and LH β mRNA levels. The present study showed that T differentially regulates LHRH and LH mRNA levels, suggesting that the negative feedback action of T on LH gene expression may be mainly due to the direct action of T on pituitary gonadtropes.
|Number of pages||8|
|Publication status||Published - 1994|
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Endocrine and Autonomic Systems
- Clinical Neurology
- Psychiatry and Mental health