Horm Metab Res 2006; 38(5): 295-299
DOI: 10.1055/s-2006-925390
Original Basic
© Georg Thieme Verlag KG Stuttgart · New York

Leptin and Prolactin, but not Corticosterone, Modulate Body Weight and Thyroid Function in Protein-malnourished Lactating Rats

P.  C.  Lisboa1 , M.  C.  F.  Passos2 , S.  C.  P.  Dutra1 , I.  T.  Bonomo1 , A.  T.  A.  Denolato1 , A.  M.  Reis3 , E.  G.  Moura1
  • 1 Dept. Ciências Fisiológicas, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brasil
  • 2 Dept. Nutrição Aplicada, Instituto de Nutrição, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brasil
  • 3 Dept. Fisiologia e Biofísica, ICB, Universidade Federal de Minas Gerais, MG, Brasil
Further Information

Publication History

Received 16 September 2005

Accepted after revision 20 December 2005

Publication Date:
23 May 2006 (online)

Abstract

To understand the role of hormonal changes in the lower food ingestion and body weight in protein-restricted lactating rats as well as the higher serum T3, higher deiodination, iodide and T3 milk transfer, we measured maternal serum prolactin, leptin, TSH and corticosterone, which are hormones that could influence those parameters. After birth, dams were separated into: control-fed with a 23 % protein diet (n = 12) and PR (protein-restricted)-fed with an 8 % protein diet (n = 12). At the 4th and 21st day of lactation, half of the animals in each group were sacrificed. PR dams presented hyperleptinemia (day 4: + 20 %; day 21: + 19 %; p < 0.05) and hypoprolactinemia (day 4: - 85 %; day 21: - 92 %; p < 0.05), which could help explain the lower food consumption and body weight in lactating PR rats since leptin is anorexigenic and prolactin is orexigenic. Also, this hyperleptinemia could contribute for the increase in serum T3 of PR dams, since leptin stimulates T3 production, especially acting on deiodinases. Serum corticosterone was not different between PR and C groups, and TSH was lower only at the end of lactation. Thus, we suggest that both leptin and prolactin could play an important role in the body weight and thyroid hormone changes observed in protein-malnourished lactating rats.

References

Dr. Egberto Gaspar de Moura

Departamento de Ciências Fisiológicas · 5° andar · Instituto de Biologia · Universidade do Estado do Rio de Janeiro

Av. 28 de setembro, 87 · Rio de Janeiro, RJ, 20551-030 · Brazil

Phone: +55 (21) 25 87 61 34

Fax: +55 (21) 25 87 61 29

Email: Egberto@Pesquisador.CNPQ.br

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