Respiration rate in human pituitary tumor explants

Area of Science:

• Endocrinology
• Oncology
• Biochemistry

Background:

• Limited data exists on the metabolic activity of human pituitary tumor tissue.
• Acromegaly is a condition caused by excess growth hormone (GH).

Purpose of the Study:

• To investigate the respiration rate and hormone secretion of human pituitary adenomas causing acromegaly.
• To characterize the metabolic activity of pituitary tumor tissue in vitro.

Main Methods:

• Human pituitary adenoma samples from four acromegaly patients were cultured in vitro.
• Oxygen uptake was measured using a spectrophotorespirometric system.
• Growth hormone (GH) and prolactin (PRL) secretion rates were quantified.

Main Results:

• Pituitary tumor tissue respiration rates were approximately 1-1.5 µL O2/h/µg dry weight.
• GH secretion rates varied from 0.1-100 pmol/µg dry weight/h, and PRL secretion rates from 0.4-18 µg/µg dry weight/h.
• Respiration and hormone secretion rates were time-dependent and varied within individual tumors.

Conclusions:

• Pituitary tumor metabolic activity can be assessed by respiration and hormone secretion rates.
• Tumor respiration rate is not a reliable indicator of GH or PRL serum levels or clinical acromegaly activity.