Lactation modulates diurnal expression profiles of specific leptin receptor isoforms in the rat hypothalamus

in Journal of Endocrinology
Authors:
RG Denis
Search for other papers by RG Denis in
Current site
Google Scholar
PubMed
Close
,
C Bing
Search for other papers by C Bing in
Current site
Google Scholar
PubMed
Close
,
EK Naderali
Search for other papers by EK Naderali in
Current site
Google Scholar
PubMed
Close
,
RG Vernon
Search for other papers by RG Vernon in
Current site
Google Scholar
PubMed
Close
, and
G Williams
Search for other papers by G Williams in
Current site
Google Scholar
PubMed
Close
Free access

Sign up for journal news

We investigated the effects of lactation on diurnal changes in serum leptin and hypothalamic expression of the leptin receptor isoforms, Ob-Ra, -Rb, -Rc, -Re and -Rf in rats. In non-lactating rats, serum leptin concentration was increased at night while hypothalamic mRNA levels of Ob-Rb, -Rc and -Re decreased; by contrast, expression of Ob-Ra and Ob-Rf was unchanged at night. There were significant negative correlations between serum leptin and mRNA expression of Ob-Rb (P<0.001) and Ob-Re (P<0.05), which were independent of time of day. In lactating rats, the nocturnal rise in serum leptin was attenuated. Daytime hypothalamic Ob-Rb mRNA levels were significantly lower than in non-lactating controls, and the normal nocturnal decreases in expression of Ob-Rb, -Rc and -Re were lost. The relationship between serum leptin and Ob-Re expression was not changed by lactation. Lactation had no effect on the expression of Ob-Ra mRNA in the hypothalamus. Decreased daytime Ob-Rb expression could lead to reduced hypothalamic sensitivity to leptin, and thus contribute to increased daytime appetite in lactating rats. Moreover, maintaining high levels of Ob-Re expression could, by increasing hypothalamic leptin-binding protein concentration and reducing local leptin bioavailability, further accentuate hyperphagia. Thus, selective changes in expression of specific isoforms of the leptin receptor may contribute to the hyperphagia of lactation in rats.

 

  • Collapse
  • Expand