ALTERATION OF SOMATOSTATIN BUT NOT GROWTH HORMONE-RELEASING FACTOR PITUITARY BINDING-SITES IN OBESE ZUCKER RATS

Title

ALTERATION OF SOMATOSTATIN BUT NOT GROWTH HORMONE-RELEASING FACTOR PITUITARY BINDING-SITES IN OBESE ZUCKER RATS

Creator

Abribat T; Finkelstein J A; Gaudreau P

Publisher

Regulatory Peptides

Date

1991
1991-10

Description

The present study was designed to determine whether the diminution of growth hormone (GH) secretion that occurs in obese Zucker rats is related to alterations of GH-releasing factor (GRF) or somatostatin (SRIF) pituitary binding sites. Cold saturation studies were performed in pituitary homogenates of 4-month-old lean and obese rats, using [I-125-Tyr-10]hGRF(1-44)NH-2 as radioligand and [I-127-Tyr-10]hGRF-(1-44)NH-2 as competitor, and in pituitary membrane preparations, using [I-125-Tyr-0, D-Trp-8]SRIF14 as radioligand and [I-127-Tyr-0, D-Trp-8]SRIF14 as competitor. In lean rats, analysis of the curves by the Ligand program revealed the presence of two distinct classes of GRF binding sites, the first being of high affinity (0.74 +/- 0.11 nM) and low capacity (118 +/- 31 fmol/mg protein), the second being of lower affinity (880 +/- 240 nM) and higher capacity (140 +/- 35 pmol/mg protein), and of a single class of SRIF binding sites (affinity: 0.40 +/- 0.12 nM; capacity: 24 +/- 6 fmol/mg protein). In obese rats, no difference was observed in GRF binding parameters for both classes of sites, but the concentration of somatostatin binding sites was reduced by 67% when compared to their lean littermates. These findings suggest that the SRIF pituitary receptors are down-regulated in obese Zucker rats and indicate that no alteration of GRF pituitary binding sites contribute to the blunted GH secretion observed in this model of obesity.

Subject

binding site; cells; defect; Endocrinology & Metabolism; growth hormone-releasing factor; hypothalamus; messenger-rna; Physiology; pituitary; secretion; somatostatin; tissue; zucker rat

Format

Journal Article or Conference Abstract Publication

Search for Full-text

Users with a NEOMED Library login can search for full-text journal articles at the following url: https://libraryguides.neomed.edu/home

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

263-270

Issue

2

Volume

36

Citation

Abribat T; Finkelstein J A; Gaudreau P, “ALTERATION OF SOMATOSTATIN BUT NOT GROWTH HORMONE-RELEASING FACTOR PITUITARY BINDING-SITES IN OBESE ZUCKER RATS,” NEOMED Bibliography Database, accessed May 14, 2021, https://neomed.omeka.net/items/show/8405.

Social Bookmarking