The effects of chlorphentermine and phentermine on certain metabolic parameters associated with development of rat kidney and liver

Transcript of protein kinase A knock-down modulates feeding behavior and neuropeptide Y gene expression in phenylpropanolamine-treated rats

Neuropeptide Y (NPY) is an appetite-controlling neuromodulator that contributes to the appetite-suppressing effect of phenylpropanolamine (PPA). Aims of this study were to investigate whether protein kinase A (PKA) signaling is involved in regulating NPY gene expression and PPA-induced anorexia. Rats were given daily with PPA for 5 days. Changes in daily food intake and hypothalamic NPY, PKA, cAMP response element binding protein (CREB), and pro-opiomelanocortin (POMC) gene expression were measured and compared. To further determine if PKA was involved, intracerebroventricular infusions of antisense oligodeoxynucleotide were performed at 60 min before daily PPA treatment in freely moving rats. Results showed that daily PKA, CREB, and POMC expression were increased following PPA treatment, which showed a closely reverse relationship with alterations of decreased feeding behaviors and NPY mRNA levels. Results also showed that PKA knock-down could block PPA-induced anorexia as well as restore NPY mRNA level, indicating the involvement of PKA signaling in the regulation of NPY gene expression. It is suggested that hypothalamic PKA signaling may participate in the central regulation of PPA-mediated appetite suppression via the modulation of hypothalamic NPY gene expression. The present findings reveal that manipulations at the molecular level of PKA or cAMP may allow the development of therapeutic agents to improve the undesirable properties of PPA or other amphetamine-like anorectic drugs.

Renal and hepatic nucleic acid metabolism in neonates: relation to experimental duration, chlorphentermine dose as well as subsequent withdrawal

Daily oral administration of either 20, 40 or 60 mg/kg chlorphentermine for 7 days significantly increased liver and kidney DNA levels, which were not elevated further even after a 3 week treatment period. Although cessation of drug administration for 3 weeks resulted in a return of hepatic DNA levels to control values, a rise in renal DNA was still observed after this withdrawal period. Whereas 20 mg/kg chlorphentermine for 7 days failed to markedly alter the incorporation of thymidine into kidney and liver DNA, significant enhancement was noted in neonates receiving 40 or 60 mg/kg drug and quantitatively greater incorporation occurred when the agent was given for 21 days. While a signficant augmentation in nucleic acids synthesis was seen 1 week after animals were removed from 40 or 60 mg/kg anorectic, a restoration to control levels occurred after a 3 week abstinence period. Treatment with 20 mg/kg for 1 week followed by withdrawal resulted in a significant rise in the incorporation of thymidine into renal and hepatic DNA. In contrast, drug administration for 3 weeks followed by 21 days abstinence resulted in a return to control levels in the incorporation of thymidine into kidney and liver DNA, except for renal tissue removed from 20 mg/kg. Our data demonstrate that the chlorphentermine-induced alterations in renal and hepatic DNA metabolism are dose-dependent, related to duration of exposure as well as reversible.