---
title: Do changes in blood plasma explain enzyme abnormalities in PMS?
description: No. Although plasma from both PMS and non-PMS women inhibited an enzyme involved in neurotransmitters, the study found no evidence that changes in plasma subs
url: https://niyora.com/research/papers/effect-of-plasma-from-premenstrual-syndrome-and-control-patients-on-human-1992/
---

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- Do changes in blood plasma explain enzyme abnormalities in PMS?

Case-control study, 1992

# Do changes in blood plasma explain enzyme abnormalities in PMS?

No. Although plasma from both PMS and non-PMS women inhibited an enzyme involved in neurotransmitters, the study found no evidence that changes in plasma substance levels explain the enzyme changes seen in PMS patients.

 Early or limited evidence

PMS patients and control subjects (sample size not stated)

## What they did

Laboratory study measuring monoamine oxidase (MAO) enzyme activity in platelets from PMS patients and controls during both premenstrual and postmenstrual phases. Plasma from both groups was tested on human platelets and rat brain tissue to see if it affected enzyme activity.

## What they found

Platelet MAO enzyme activity (Vmax) was significantly lower in the postmenstrual phase compared to premenstrual phase in PMS patients. Plasma from both PMS and control groups inhibited the enzyme in a dose-dependent manner (at 10-100 microliters) to approximately the same degree at each time interval.

## What it means for you

While PMS may involve changes in this enzyme, the study did not find the suspected mechanism. This is a laboratory study that does not directly address whether enzyme changes cause PMS symptoms. The findings suggest other mechanisms need investigation.

10-100

Plasma volume tested in microliters

## About the study

Original title Effect of plasma from premenstrual syndrome and control patients on human platelet and rat brain synaptosome monoamine oxidase B activity Authors Ashby CR Jr, Carr LA, Cook C et al. Journal Neuropsychobiology Year 1992 Study design Case-control study What was tested None (laboratory study) Read the paper [doi.org/10.1159/000118820](https://doi.org/10.1159/000118820)

## Topics

[Premenstrual syndrome (PMS)](https://niyora.com/research/topics/condition-pms/)

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