Naloxone increases the response of growth hormone and prolactin to stimuli in obese humans
Opiates stimulate the growth hormone and prolactin responses to stimuli in non-obese humans. Obese patients, however, show lowered growth hormone and prolactin responses and raised β-endorphin levels. We therefore investigated the effect of the opiate antagonist naloxone on the stimulated growth hormone and prolactin secretions in a controlled double-blind study in obese patients. All patients received 200µg TRH and 0.5 g/kg b.w. arginine together with 2 mg of naloxone or placebo i.v. in a randomized sequence. The TRH- and arginine-induced increases in prolactin and growth hormone were significantly greater after administration of naloxone (p < 0.05). Naloxone also produced a significant increase in ACTH, Cortisol and β-endorphin when compared with placebo. TSH, triiodothyronine, thyroxine, insulin, glucagon and blood glucose showed no significant differences between both days of the trial. The effect of naloxone on growth hormone and prolactin secretions in obese humans can thus be regarded as a partial normalization. We therefore conclude that the hypothalamic regulatory disturbance of growth hormone and prolactin secretions in the obese could be caused by raised opiate levels.
Key-wordsβ-endorphin growth hormone prolactin naloxone obesity
Unable to display preview. Download preview PDF.
- 6.Demura R., Suda T., Wakabayashi I., Yoshimura M., Jibiki K., Odagiri E., Demura H., Shimuze K. Plasma pituitary hormone response to the synthetic enkephalin analog (FK33-824) in normal subjects and patients with pituitary diseases. J. Clin. Endocrinol. Metab. 52: 263, 1981.PubMedCrossRefGoogle Scholar
- 24.Copinschi G., Cornie A., Leclercq R., Frankson J.R.M. Cortisol secretion rate and urinary corticoid excretion in normal and obese subjects. Acta Endocrinol. (Kbh.) 51: 186, 1966.Google Scholar
- 29.Naber D., Pickar D., Davis G.C., Cohen R.M., Jimerson D.C., Elchisak M.A., Defraites E.G., Kalin N.H., Risch S.C., Buchsbaum M.S. Naloxone effects on β-endorphin, Cortisol, prolactin, growth hormone, HVA and MHPG in plasma of normal volunteers. Psychopharmacology 74: 125, 1981.PubMedCrossRefGoogle Scholar