Clinical trial NCT05208684: Prolactin Release Through Breast Stimulation in Non-lactating Women - Who Does Respond?
Official title: Prolactin Release Through Breast Stimulation in Non-lactating Women - Who Does Respond?
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Prolactin
Breast Stimulation
Lead sponsor: University Hospital Tuebingen
Sponsor class: OTHER
First posted: 2022-01-26
Enrollment: 40
Sex: FEMALE
Minimum age (years): 18
Maximum age (years): 45
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: OTHER

Brief summary: Prolactin is a multifunctional hormone which acts in different cell types rather than just modulating reproduction and lactation. One additional point is its action on glucose metabolism which is described especially in rodents. Prolactin affects proliferation, survival and insulin production of pancreatic beta cells in animal models. But also in human studies prolactin is linked to insulin action. Low systemic levels of prolactin are associated with increased prevalence of diabetes and while higher levels are associated with higher insulin sensitivity.

Acute metabolic effects of prolactin in young, healthy and non-lactating women should be accessed. Therefore, the induction of a transient increase of circulating prolactin levels is necessary to study the acute effects of this hormone on metabolic processes. This can most likely be achieved in non-pregnant and non-lactating women without pharmacological intervention.

As the main stimulus of prolactin release from the pituitary gland is the mechanical stimulation of the breast / nipple, like a suckling baby, stimulation by a breast pump might trigger prolactin release.

Due to other studies in this field, only a minority of women respond to breast stimulation with an increase in prolactin levels. Therefore, this pilot study will assess if an electric milk pump can stimulate prolactin release in non-lactating women. The second aim of the study is to identify factors which determine response and non-response to breast stimulation.

Prolactin will be measured in blood serum. The primary objective of this study is to identify women in whom a 30-minute breast stimulation causes a marked prolactin release. Response is defined as an increase at least twice the baseline value.

Second outcomes are the quantification and duration of prolactin increase as well as to detect differences in responders and non-responders. Therefore, demographic data as well as anthropometric data will also be assessed. A 10-minute electrocardiography and non-invasive measurement of resting energy expenditure by indirect calorimetry will also be performed. History of menstrual cycle, intake of contraceptive, parity and lactation experience will be recorded. Physical activity level and feeling of hunger will be assessed by questionnaires.

Feeling of hunger, resting energy expenditure, blood pressure, heart rate and body temperature will be assessed repeatedly to register differences before and after stimulation. Blood and urine samples will be assessed for safety.


Eligibility criteria: Inclusion Criteria:

* Women, aged between 18 and 45 years
* premenopausal (women, who had menses at any time in the preceding 24 consecutive months)
* BMI \< 25 kg/m²
* Ability to understand and voluntarily sign an informed consent document prior to any study related procedures

Exclusion Criteria:

* Type 1 or Type 2 diabetes
* Intake of medication which may affect prolactin levels (e.g. Metoclopramide, Methyldopa, opiates, cimetidine), except birth control pill/hormonal contraception known hyperprolactinemia or hyperthyroidism
* any other serious illness that might impact the results as judged by the investigator (e.g. malignant disease, coronary heart disease)
* Pregnant / breastfeeding women (weaning at least 6 month ago)
* plastic breast surgery (with detachment of milk ducts)
* allergy to BPA-free plastic

Primary outcomes:
measure: Prolactin release - yes/no
timeFrame: Sample collection will be from 0 to 90 minutes
Secondary outcomes:
measure: Prolactin levels
timeFrame: Sample collection will be from 0 to 90 minutes
measure: Differences in subjects age
timeFrame: 1 minute
measure: Differences in subjects BMI
timeFrame: 4 minutes
measure: Differences in subjects body fat content
timeFrame: 3 minutes
measure: Differences in subjects menstrual cycle phase
timeFrame: 2 minutes
measure: Differences in subjects intake of hormonal contraception
timeFrame: 2 minutes
measure: Differences in subjects parity
timeFrame: 2 minutes
measure: Differences in subjects history of lactation
timeFrame: 2 minutes
measure: Differences in subjects heart rate variability parameters: time domain (beats per minute)
timeFrame: 10 minutes
measure: Differences in subjects heart rate variability parameters: Root Mean Square of successive RR interval differences (RMSSD)
timeFrame: 10 minutes
measure: Differences in subjects heart rate variability parameters: Standard deviation of RR-intervals (SDNN)
timeFrame: 10 minutes
measure: Differences in subjects heart rate variability parameters: frequency domain parameters
timeFrame: 10 minutes
measure: Differences in subjects heart rate variability parameters: Low to high frequency power ratio
timeFrame: 20 minutes
measure: Differences in subjects physical activity level
timeFrame: 10 minutes
measure: Differences in subjects stress reaction
timeFrame: Sample collection will be from 0 to 90 minutes
measure: Changes in feelings of hunger through stimulation
timeFrame: 10 minutes
measure: Changes in resting energy expenditure through stimulation
timeFrame: 30 minutes (each 15 minutes)
measure: Changes in blood pressure through stimulation
timeFrame: 4 minutes
measure: Changes in heart rate through stimulation
timeFrame: 4 minutes
measure: Changes in body temperature through stimulation
timeFrame: 1 minute
measure: Changes of Hypothalamic-Pituitary-Adrenal axis activity
timeFrame: 90 minutes
measure: Changes of Hypothalamic-Pituitary-Somatotropic axis activity
timeFrame: 90 minutes
measure: Changes of Hypothalamic-Pituitary-Prolactin axis activity
timeFrame: 90 minutes
measure: Changes of Hypothalamic-Pituitary-Thyroid axis activity
timeFrame: 90 minutes
measure: Changes of Hypothalamic-Pituitary-Gonadal axis activity
timeFrame: 90 minutes
Other outcomes:
Locations:
city: Tuebingen
country: Germany
facility: University Hospital Tuebingen, Otfried-Mueller Str. 10
Study officials:
References: