Corticotrophin-releasing factor-like immunoreactivity and mRNA in human leukocytes

Unstimulated normal leukocytes were studied for their expression of corticotrophin-releasing factor (CRF)-like mRNA and peptide. In situ hybridization demonstrated CRF mRNA in T and B lymphocytes and in neutrophils. Northern blot analysis also detected the presence of a CRF mRNA species of approximately 1.7 Kb from lymphocytes and a peptide that reacted with anti-CRF antiserum was also detected by radioimmunoassay. This lymphocyte-derived peptide eluted earlier than standard CRF on high performance liquid chromatography. These findings suggest that regulatory mechanisms within the hypothalamus and the immune system may utilize closely related peptides.

Distribution of immunoreactive growth hormone-releasing hormone in the human brain and intestine and its production by tumors

A recently developed RIA for human pancreatic tumor GH-releasing hormone (hpGRH1-44NH2) was used to investigate its distribution in the human gastrointestinal tract and brain, and to determine the incidence of its production by tumors. GRH-immunoreactivity (GRH-IR) was present in several regions of the human brain, the highest concentration occurring in the hypothalamus, septum, and substantia inominata. In the gastrointestinal tract GRH-IR was present in the upper intestine, where it was confined to the epithelial mucosa. Approximately one third of all tumors examined (35 out of 97) contained significant amounts of GRH-IR. Gel chromatography of brain and intestinal extracts, and of several tumors, revealed the presence of two molecular forms of GRH-IR, one coeluting with the synthetic hpGRH1-44 amide standard (and also hpGRH1-40) and another eluting significantly later. The earlier eluting GRH-IR peak was found to be similar to the synthetic hpGRH1-44 NH2 and hpGRH1-40 on high pressure liquid chromatography analysis.