18月龄雌性大鼠下丘脑内源性阿片肽含量及其mRNA水平变化的研究

本文应用分子生物学和放射免疫测定方法，观察了老年前期雌性大鼠下丘脑、垂体和血浆中内阿片肽含量及下丘脑内阿片肽基因表达的变化．与5月龄青年大鼠比较，18月龄雌性大鼠下丘脑和血浆β-EP、L－ENK、Dy－nA含量减少，垂体β-EP、L－ENK含量升高，DynA含量降低（P＜0．05～0．01）．下丘脑POMC基因和proenkepbalin基因mRNA水平明显低于青年大鼠（P＜0．05）．结果提示，老年前期雌性大鼠下丘脑内阿片肽合成能力减退，衰老对下丘脑和垂体内阿片肽调节机制的影响有所不同．

AGING CHANGES IN ENDOGENOUS OPIOID PEPTIDES CONTENTS AND mRNA LEVELS OF THE HYPOTHALAMUS IN 18 MONTH OLD FEMALE RATS

In the present study, endogenous opioid peptide (EOP) mRNA levels in the hypothalamus, the contents in the hypothalamus, pituitary and plasma of young(5 months)and old (18 months ) fernale rats were measured by Northern Blot and specific radioimmunoassay. The POMC and proenkephalin gene mRNA levels were lower in the hypothalamus of old rats (18 months old)than that of young rats(5 months old) (P<0.05). The concentrations of β-endorphin, leu-enkephalin and dynorPhinA1-13 of the bypothalamus and plasma, and the dynorphinA1-13 content of the pituitary were also lower in old rats compared to that in young rats(P<0.05~0.01), while the pituitary aendorphin and leu-enkephalin contents were increased in aged rats (P<0.05~0.01). Thus, it seems that the regulatory mechanisms in the hypothalamus and pituitary are differ-entially affected by increasing age. These results indicate that the synthesis of EoP is reduced with advancing age in the hy Pothalamus of 18 month old female rats.