Progesterone and norethisterone have different effects on tachykinin-like immunoreactivity in rat cortex and striatum.
OBJECTIVE
The purpose of this study was to investigate the effects of progesterone and the most commonly prescribed synthetic progestogen, norethisterone, on regional immune-like reactivity of neuropeptide Y (NPY), substance P (SP), neurokinin A (NKA) and neurotensin (NT) in brains of female ovariectomized estradiol-substituted rats.


RESULTS
Norethisterone+estradiol-treated rats had 44% lower SP levels compared with estradiol-only-treated in frontal cortex and 20% lower NKA levels in comparison with progesterone+estradiol-treated in frontal cortex. Progesterone+estradiol-treated rats had 66% lower SP levels in striatum in comparison with both estradiol-only-treated and norethisterone+estradiol-treated. No significant results were found for NPY and NT.


CONCLUSIONS
Progesterone and the synthetic progestogen, norethisterone, have different effects on SP- and NKA-like immunoreactivity in rat cortex and striatum. The effects of NET on SP- and NKA-like immunoreactivity in frontal cortex may contribute to the mood effects ascribed to this progestogen in clinical usage.
Rugarn
O
O
Faculty of Health Sciences, Division of Obstetrics and Gynecology, Linköping University Hospital, S-581 85, Linköping, Sweden. mats.hammar@kkl.us.lio.se
Hammar
M
M
Theodorsson
E
E
D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism*; D003692:Delayed-Action Preparations; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D006624:Hippocampus / Q000378:metabolism; D017072:Neostriatum / Q000378:metabolism*; D015288:Neurokinin A / Q000276:immunology / Q000378:metabolism; D009478:Neuropeptide Y / Q000276:immunology / Q000378:metabolism; D009496:Neurotensin / Q000276:immunology / Q000378:metabolism; D009640:Norethindrone / Q000008:administration & dosage / Q000494:pharmacology*; D010052:Ovariectomy; D011374:Progesterone / Q000008:administration & dosage / Q000494:pharmacology*; D045167:Progesterone Congeners / Q000008:administration & dosage / Q000494:pharmacology*; D011863:Radioimmunoassay; D051381:Rats; D013373:Substance P / Q000276:immunology / Q000378:metabolism; D015320:Tachykinins / Q000276:immunology / Q000378:metabolism*
D003692:Delayed-Action Preparations; D009478:Neuropeptide Y; D045167:Progesterone Congeners; D015320:Tachykinins; D013373:Substance P; D009496:Neurotensin; D011374:Progesterone; D004958:Estradiol; D015288:Neurokinin A; D009640:Norethindrone