Methods: Tissues were obtained from surgical specimens of seven females with STC and six controls. Feasibility studies were performed in biopsies from six patients with STC and three controls. P4R, SERT and TPH-1 mRNA and protein expression and 5-HT by ELISA were determined. Contraction was studied in normal muscle cells pretreated with P4 or buffer. Progesterone effects on SERT and 5-HT levels were studied in normal human mucosa in vitro and in wild and SERT knockout mice in vivo.
Key results: P4R was overexpressed in epithelial cells in STC compared with controls. The levels of SERT were lower and 5-HT higher in STC. In epithelial cells P4 treatment decreased SERT and increased mucosal 5-HT without affecting TPH-1. Progesterone impaired the contraction of normal muscle cells induced by Ach and 5-HT. Progesterone decreased SERT and increased 5-HT levels in the colon of wild mice in vivo but had no effect on the high basal levels of 5-HT in SERT knockout mice.
Conclusions & inferences: P4R are present in colon epithelial cells and are overexpressed in females with STC. These cells have reduced SERT and high 5-HT levels and normal TPH-1. These 5-HT signaling abnormalities are related to overexpression of P4R since they are reproduced in human epithelial cells in vitro and in mice in vivo.
P4 raises 5ht and lowers SERT in cells :/
If it does this throughout the body be sure not to take other things that block SERT such as too much vitamin d or of course an ssri, personally I had problems of high serotonin with vitamin d (4000iu) with around 20mg p4 , constipation and worryingly testicular pain as well as a depressed defeated mood.
Melatonin inhibits SERT mediated 5‐HT uptake in human and mouse derived platelets and synaptosomes
Melatonin also increases the action of progesterone/ is anti estrogenic and in my case taking high doese p4 and melatonin 3mg would block sert action even more so be careful with that combo.