Combined pituitary hormone deficiency in German shepherd dogs with dwarfism

Ghrelin-stimulation test in the diagnosis of canine pituitary dwarfism

“…In addition, ACTH and consequently cortisol secretion seemed to be preserved in the dwarf dogs. In contrast with the study of Kooistra et al (2000), we found that the basal plasma LH concentration was significantly higher in the dogs with pituitary dwarfism. This unexpected finding warrants further investigation of basal LH secretion in German shepherd dwarfs with combined pituitary hormone deficiency.…”

“…In line with earlier findings in German shepherd dwarf dogs (Hamann et al, 1999;Kooistra et al, 2000), the basal plasma TSH and PRL concentrations in these dogs were significantly lower than those in healthy dogs. In addition, ACTH and consequently cortisol secretion seemed to be preserved in the dwarf dogs.…”

“…In GH-deficient human adults, circulating IGF-1 levels are within the reference range in about 60% of cases (Gill et al, 1998). In accordance with previous canine studies (Eigenmann et al, 1984;Rijnberk et al, 1993;Kooistra et al, 1998Kooistra et al, , 2000, the mean basal plasma IGF-1 concentration in the pituitary dwarfs was lower than that in the healthy dogs, but due to a considerable overlap this difference did not reach statistical significance. Thus, because of comparable plasma concentrations of GH and IGF-1 between pituitary dwarfs and healthy individuals, the diagnosis of GH deficiency has to be based upon the results of a stimulation test.…”

“…Assessment of random basal plasma GH concentrations is inadequate for documentation of hyposomatotropism, because circulating GH concentrations in healthy dogs and pituitary dwarfs may overlap (Kooistra et al, 2000). Indeed, the results of this study illustrate the absence of a significant difference in basal plasma GH concentration between healthy dogs and German shepherd dogs with pituitary dwarfism.…”

“…An absolute deficiency of GH, PRL and thyroid-stimulating hormone (TSH) is associated with an impaired release of gonadotrophins, whereas ACTH secretion is preserved (Hamann et al, 1999;Kooistra et al, 2000). The abnormality in these dwarfs is most likely caused by a mutation in a developmental transcription factor that precludes effective expansion of a pituitary stem cell after the differentiation of the corticotroph cells (Kooistra et al, 2000). To date, sequence analysis of genomic DNA from German shepherd dwarfs has not revealed causative mutations in candidate genes (Lantinga-van Leeuwen et al, 2000a,b;van Oost et al, 2002).…”