Suppression of leptin during lactation

contribution of the suckling stimulus versus milk production

Rebecca S Brogan, Sharon E Mitchell, Paul Trayhurn, M. Susan Smith

Research output: Contribution to journalArticle

89 Citations (Scopus)

Abstract

Lactation in the rat is characterized by the suppression of pulsatile LH secretion, a large increase in food intake, and changes in energy balance due to the metabolic drain of milk production. The change in energy balance may be a major component in altering reproductive function. A number of factors may contribute to changing energy balance of a lactating animal; one is leptin, the product of adipose tissue, which is known to act partly as a satiety factor to decrease food intake. The aims of the present study were to determine whether there are changes in leptin levels during lactation, a state of high energy demand, and during periods of acute suckling in the presence or absence of changes in energy demand. Our goals were to determine whether lactation and the suckling stimulus influenced serum leptin levels and whether there was a potential role for leptin in the suppression of LH secretion during lactation. The first experiment was performed during diestrus of the estrous cycle, and chronic lactation, (day 9 post partum) in animals suckling 8 pups. The results showed that leptin levels were significantly decreased in both ovarian intact or ovariectomized lactators; this decrease parallels the suppression of pulsatile LH secretion. Serum insulin levels were not altered in the lactating animals. The second experiment was performed in ovariectomized lactators whose 8 pup litters were removed for 48 h, starting on day 9. On day 11, mothers received no pups or pups that were either nonfostered (resulting in no milk production) or fostered (resulting in milk production). The pups were allowed to suckle for 24 h. Following 24 h of acute suckling, serum leptin, and insulin levels correlated with the energy drain on the mother. The levels of leptin were normal and of insulin were elevated in mothers producing no milk. Conversely, leptin levels were suppressed and insulin levels normal in mothers producing milk. The third experiment used the same groups as described for the second experiment except that serial blood samples were collected for measurement of pulsatile LH secretion following 24 h of acute suckling. The results showed that regardless of whether leptin levels remained normal or were suppressed in response to acute suckling, pulsatile LH secretion was significantly inhibited compared with the nonsuckled control animals. In summary, these data suggest that the metabolic drain of milk production, and not the suckling stimulus itself, is the most likely factor responsible for the suppression of leptin secretion during lactation. Furthermore, although the decreased levels of leptin may be causally related to the inhibition of pulsatile LH secretion during chronic lactation, changes in leptin are not a prerequisite for the suppression of LH secretion in response to suckling.
Original languageEnglish
Pages (from-to)2621-2627
Number of pages7
JournalEndocrinology
Volume140
Issue number6
DOIs
Publication statusPublished - 1999

Fingerprint

Leptin
Lactation
Milk
Insulin
Suckling Animals
Eating
Serum
Diestrus
Estrous Cycle
Adipose Tissue

Keywords

  • Animals
  • Animals, Suckling
  • Female
  • Insulin
  • Lactation
  • Leptin
  • Luteinizing Hormone
  • Oxytocin
  • Prolactin
  • Proteins
  • Rats
  • Rats, Sprague-Dawley

Cite this

Suppression of leptin during lactation : contribution of the suckling stimulus versus milk production. / Brogan, Rebecca S; Mitchell, Sharon E; Trayhurn, Paul; Smith, M. Susan.

In: Endocrinology, Vol. 140, No. 6, 1999, p. 2621-2627.

Research output: Contribution to journalArticle

Brogan, Rebecca S ; Mitchell, Sharon E ; Trayhurn, Paul ; Smith, M. Susan. / Suppression of leptin during lactation : contribution of the suckling stimulus versus milk production. In: Endocrinology. 1999 ; Vol. 140, No. 6. pp. 2621-2627.
@article{fe519e6b7f1c4f63b777ec3f2bea41d9,
title = "Suppression of leptin during lactation: contribution of the suckling stimulus versus milk production",
abstract = "Lactation in the rat is characterized by the suppression of pulsatile LH secretion, a large increase in food intake, and changes in energy balance due to the metabolic drain of milk production. The change in energy balance may be a major component in altering reproductive function. A number of factors may contribute to changing energy balance of a lactating animal; one is leptin, the product of adipose tissue, which is known to act partly as a satiety factor to decrease food intake. The aims of the present study were to determine whether there are changes in leptin levels during lactation, a state of high energy demand, and during periods of acute suckling in the presence or absence of changes in energy demand. Our goals were to determine whether lactation and the suckling stimulus influenced serum leptin levels and whether there was a potential role for leptin in the suppression of LH secretion during lactation. The first experiment was performed during diestrus of the estrous cycle, and chronic lactation, (day 9 post partum) in animals suckling 8 pups. The results showed that leptin levels were significantly decreased in both ovarian intact or ovariectomized lactators; this decrease parallels the suppression of pulsatile LH secretion. Serum insulin levels were not altered in the lactating animals. The second experiment was performed in ovariectomized lactators whose 8 pup litters were removed for 48 h, starting on day 9. On day 11, mothers received no pups or pups that were either nonfostered (resulting in no milk production) or fostered (resulting in milk production). The pups were allowed to suckle for 24 h. Following 24 h of acute suckling, serum leptin, and insulin levels correlated with the energy drain on the mother. The levels of leptin were normal and of insulin were elevated in mothers producing no milk. Conversely, leptin levels were suppressed and insulin levels normal in mothers producing milk. The third experiment used the same groups as described for the second experiment except that serial blood samples were collected for measurement of pulsatile LH secretion following 24 h of acute suckling. The results showed that regardless of whether leptin levels remained normal or were suppressed in response to acute suckling, pulsatile LH secretion was significantly inhibited compared with the nonsuckled control animals. In summary, these data suggest that the metabolic drain of milk production, and not the suckling stimulus itself, is the most likely factor responsible for the suppression of leptin secretion during lactation. Furthermore, although the decreased levels of leptin may be causally related to the inhibition of pulsatile LH secretion during chronic lactation, changes in leptin are not a prerequisite for the suppression of LH secretion in response to suckling.",
keywords = "Animals, Animals, Suckling, Female, Insulin, Lactation, Leptin, Luteinizing Hormone, Oxytocin, Prolactin, Proteins, Rats, Rats, Sprague-Dawley",
author = "Brogan, {Rebecca S} and Mitchell, {Sharon E} and Paul Trayhurn and Smith, {M. Susan}",
year = "1999",
doi = "10.1210/endo.140.6.6802",
language = "English",
volume = "140",
pages = "2621--2627",
journal = "Endocrinology",
issn = "0013-7227",
publisher = "The Endocrine Society",
number = "6",

}

TY - JOUR

T1 - Suppression of leptin during lactation

T2 - contribution of the suckling stimulus versus milk production

AU - Brogan, Rebecca S

AU - Mitchell, Sharon E

AU - Trayhurn, Paul

AU - Smith, M. Susan

PY - 1999

Y1 - 1999

N2 - Lactation in the rat is characterized by the suppression of pulsatile LH secretion, a large increase in food intake, and changes in energy balance due to the metabolic drain of milk production. The change in energy balance may be a major component in altering reproductive function. A number of factors may contribute to changing energy balance of a lactating animal; one is leptin, the product of adipose tissue, which is known to act partly as a satiety factor to decrease food intake. The aims of the present study were to determine whether there are changes in leptin levels during lactation, a state of high energy demand, and during periods of acute suckling in the presence or absence of changes in energy demand. Our goals were to determine whether lactation and the suckling stimulus influenced serum leptin levels and whether there was a potential role for leptin in the suppression of LH secretion during lactation. The first experiment was performed during diestrus of the estrous cycle, and chronic lactation, (day 9 post partum) in animals suckling 8 pups. The results showed that leptin levels were significantly decreased in both ovarian intact or ovariectomized lactators; this decrease parallels the suppression of pulsatile LH secretion. Serum insulin levels were not altered in the lactating animals. The second experiment was performed in ovariectomized lactators whose 8 pup litters were removed for 48 h, starting on day 9. On day 11, mothers received no pups or pups that were either nonfostered (resulting in no milk production) or fostered (resulting in milk production). The pups were allowed to suckle for 24 h. Following 24 h of acute suckling, serum leptin, and insulin levels correlated with the energy drain on the mother. The levels of leptin were normal and of insulin were elevated in mothers producing no milk. Conversely, leptin levels were suppressed and insulin levels normal in mothers producing milk. The third experiment used the same groups as described for the second experiment except that serial blood samples were collected for measurement of pulsatile LH secretion following 24 h of acute suckling. The results showed that regardless of whether leptin levels remained normal or were suppressed in response to acute suckling, pulsatile LH secretion was significantly inhibited compared with the nonsuckled control animals. In summary, these data suggest that the metabolic drain of milk production, and not the suckling stimulus itself, is the most likely factor responsible for the suppression of leptin secretion during lactation. Furthermore, although the decreased levels of leptin may be causally related to the inhibition of pulsatile LH secretion during chronic lactation, changes in leptin are not a prerequisite for the suppression of LH secretion in response to suckling.

AB - Lactation in the rat is characterized by the suppression of pulsatile LH secretion, a large increase in food intake, and changes in energy balance due to the metabolic drain of milk production. The change in energy balance may be a major component in altering reproductive function. A number of factors may contribute to changing energy balance of a lactating animal; one is leptin, the product of adipose tissue, which is known to act partly as a satiety factor to decrease food intake. The aims of the present study were to determine whether there are changes in leptin levels during lactation, a state of high energy demand, and during periods of acute suckling in the presence or absence of changes in energy demand. Our goals were to determine whether lactation and the suckling stimulus influenced serum leptin levels and whether there was a potential role for leptin in the suppression of LH secretion during lactation. The first experiment was performed during diestrus of the estrous cycle, and chronic lactation, (day 9 post partum) in animals suckling 8 pups. The results showed that leptin levels were significantly decreased in both ovarian intact or ovariectomized lactators; this decrease parallels the suppression of pulsatile LH secretion. Serum insulin levels were not altered in the lactating animals. The second experiment was performed in ovariectomized lactators whose 8 pup litters were removed for 48 h, starting on day 9. On day 11, mothers received no pups or pups that were either nonfostered (resulting in no milk production) or fostered (resulting in milk production). The pups were allowed to suckle for 24 h. Following 24 h of acute suckling, serum leptin, and insulin levels correlated with the energy drain on the mother. The levels of leptin were normal and of insulin were elevated in mothers producing no milk. Conversely, leptin levels were suppressed and insulin levels normal in mothers producing milk. The third experiment used the same groups as described for the second experiment except that serial blood samples were collected for measurement of pulsatile LH secretion following 24 h of acute suckling. The results showed that regardless of whether leptin levels remained normal or were suppressed in response to acute suckling, pulsatile LH secretion was significantly inhibited compared with the nonsuckled control animals. In summary, these data suggest that the metabolic drain of milk production, and not the suckling stimulus itself, is the most likely factor responsible for the suppression of leptin secretion during lactation. Furthermore, although the decreased levels of leptin may be causally related to the inhibition of pulsatile LH secretion during chronic lactation, changes in leptin are not a prerequisite for the suppression of LH secretion in response to suckling.

KW - Animals

KW - Animals, Suckling

KW - Female

KW - Insulin

KW - Lactation

KW - Leptin

KW - Luteinizing Hormone

KW - Oxytocin

KW - Prolactin

KW - Proteins

KW - Rats

KW - Rats, Sprague-Dawley

U2 - 10.1210/endo.140.6.6802

DO - 10.1210/endo.140.6.6802

M3 - Article

VL - 140

SP - 2621

EP - 2627

JO - Endocrinology

JF - Endocrinology

SN - 0013-7227

IS - 6

ER -