Expression of vasoactive intestinal peptide/peptide histidine isoleucine in several hypothalamic areas during the
1Department of Animal Science, University of Minnesota, St. Paul, Minn., USA.
Abstract:
The present study examined the changes in vasoactive intestinal peptide (VIP) and peptide histidine isoleucine (PHI) gene expression in the hypothalamus and compared their level of expression to prolactin (PRL) secretion throughout the turkey reproductive cycle. Both VIP and PHI expression were determined using in situ hybridization histochemistry and reverse transcription-polymerase chain reaction/Southern blot analysis. Plasma PRL levels were determined by radioimmunoassay. The changes in total hypothalamic VIP and PHI mRNA steady-state levels mirrored the changes seen in plasma PRL across the reproductive stages. In situ hybridization revealed that VIP mRNA was highly expressed throughout the hypothalamus and predominated within the ventromedial nucleus (VMN), inferior hypothalamus, and infundibular nuclear complex (INF). PHI mRNA was expressed in very low abundance within the same areas expressing VIP mRNA. VIP mRNA abundance within the VMN and INF was lowest in nonphotostimulated hens (VMN, 13.8 +/- 1.7; INF, 17.0 +/- 1.8 arbitrary densitometric units (ADU)), intermediate in laying hens (VMN, 29.6 +/- 3.3; INF, 35.4 +/- 4.3 ADU), and highest in incubating hens (VMN, 76.4 +/- 10.2; INF, 119.2 +/- 3.4 ADU). Levels decreased when birds shifted from incubation to photorefractoriness (VMN, 75%; INF, 82%). This relationship was not observed within other areas of the hypothalamus. The expression of PHI mRNA was also highest in the VMN and INF of incubating hens but no correlation between PHI mRNA and the other reproductive states was observed. This study provides additional evidence that VIP is the avian PRL-releasing factor, and suggests that the central site for avian PRL regulation lies within the INF of the hypothalamus.
More Related Videos
11:04Unraveling the Role of Discrete Areas of the Rat Brain in the Regulation of Ovulation through Reversible Inactivation by Tetrodotoxin Microinjections
Published on: September 3, 2020
09:30Dual Somatic Recordings from Gonadotropin-Releasing Hormone (GnRH) Neurons Identified by Green Fluorescent Protein (GFP) in Hypothalamic Slices
Published on: February 23, 2010
Related Concept Videos
Hormones of the Pituitary Gland
The most abundantly secreted hormone from the anterior lobe is the growth hormone, which controls overall growth by...
Hormonal Regulation
Regulation of Hormone Secretion
Humoral stimuli,...
Regulation of Food Intake
Diencephalon: Hypothalamus and Coordination
The hypothalamus interacts with other brain regions, including the pituitary gland, through a direct physical connection called the hypothalamic-pituitary axis. The hypothalamus receives somatic and visceral inputs and...
The Pituitary Gland
