Prolonged inhibition of presynaptic catecholamine synthesis does not alter leptin secretion in normal-weight men and women

Ralf C. Zimmermann, Lois Elaine Krahn, Nooria Rahmanie, Mark V. Sauer

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Leptin has been called a hormone of reproduction, and seems to link fat and fertility. It has been speculated that the neurotransmitter norepinephrine (NE) (noradrenaline), possibly via the sympathetic nervous system, may represent the afferent signal which modulates leptin release from adipocytes. The purpose of this study was to produce a state of decreased sympathetic output by using the catecholamine synthesis inhibitor alpha-methyl-para-tyrosine (AMPT), in order to study the effect of this compound on the secretion of leptin from fat cells. Ten subjects (five women and five men) received a total of 5 x 1 g doses of AMPT or 5 x 50 mg promethazine (active placebo) over a 26 h period, separated by 4-6 weeks using a randomized, double-blind, placebo-controlled, cross-over design. Blood samples for hormone measurements were obtained over 24 h (18 time points) on day 2 of each experiment. Urinary measurement of the NE metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) on study day 2 served as a marker of the effectiveness of AMPT as an inhibitor of NE synthesis. The daily excretion of this metabolite decreased from 1.56 ± 0.22 mg in the placebo experiment to 0.53 ± 0.1 mg in the active experiment (P < 0.05). Plasma leptin concentrations measured in the control group in women and men were similar to those reported previously in lean subjects with a body mass index < 27.5 kg/m2. Leptin concentrations in women were 3-fold higher than in men. Leptin is secreted in a circadian rhythm in both sexes with an increase of nocturnal concentrations by ~ 50%. Two-way analysis of variance reveals no significant difference in leptin secretion between the control and active groups in women and men. In summary, preliminary results do not support the hypothesis that NE represents the afferent signal from the central nervous system which modulates leptin release from adipocytes in the human. Further studies are needed to define the role of the sympathetic nervous system as well as NE in the regulation of leptin secretion and its involvement in obesity and reproduction.

Original languageEnglish (US)
Pages (from-to)822-825
Number of pages4
JournalHuman Reproduction
Volume13
Issue number4
DOIs
StatePublished - 1998

Fingerprint

Leptin
Catecholamines
Weights and Measures
Norepinephrine
alpha-Methyltyrosine
Adipocytes
Sympathetic Nervous System
Placebos
Reproduction
Hormones
Promethazine
Control Groups
Circadian Rhythm
Cross-Over Studies
Fertility
Neurotransmitter Agents
Analysis of Variance
Body Mass Index
Central Nervous System
Obesity

Keywords

  • Leptin
  • Norepinephrine
  • Sympathetic nervous system

ASJC Scopus subject areas

  • Physiology
  • Developmental Biology
  • Obstetrics and Gynecology
  • Reproductive Medicine

Cite this

Prolonged inhibition of presynaptic catecholamine synthesis does not alter leptin secretion in normal-weight men and women. / Zimmermann, Ralf C.; Krahn, Lois Elaine; Rahmanie, Nooria; Sauer, Mark V.

In: Human Reproduction, Vol. 13, No. 4, 1998, p. 822-825.

Research output: Contribution to journalArticle

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