Expression of mRNA for somatostatin receptor (sstr) types 2 and 5 in individual rat pituitary cells. A double labeling in situ hybridization analysis.
To characterize cell specific expression of sstr subtypes in the pituitary we have analyzed mRNA for sstr1-5 in rat pituitary somatotrophs by reverse transcriptase polymerase chain reaction and determined the pattern and level of expression of mRNA for sstr subtypes 2 and 5 in individual pituitary cell subpopulations by double label in situ hybridization. Purified somatotrophs expressed mRNA for all 5 sstrs. In situ hybridization analysis revealed sstr5 mRNA in 70% of somatotrophs, 57% of thyrotrophs, 38% of corticotrophs, 33% of lactotrophs, and 21% of gonadotrophs. mRNA for sstr2 occurred in 40% of somatotrophs, 36% of thyrotrophs, 26% of lactotrophs, 3% of corticotrophs, and 8% of gonadotrophs. Not only were more cells positive for sstr5 mRNA but the average number of autoradiographic grains/cell was also higher for sstr5 than sstr2. These results show expression of multiple sstr genes in individual pituitary cells. mRNA for sstr2 and 5 occur in each of the 5 major pituitary cell subsets, sstr5 mRNA being more widely and more abundantly expressed than sstr2.
Day
R
R
Fraser Laboratories, Department of Medicine, McGill University, Royal Victoria Hospital, Montreal, Quebec, Canada.
Dong
W
W
Panetta
R
R
Kraicer
J
J
Greenwood
M T
MT
Patel
Y C
YC
D000818:Animals; D001483:Base Sequence; D015870:Gene Expression; D017403:In Situ Hybridization / Q000379:methods*; D008297:Male; D008969:Molecular Sequence Data; D010902:Pituitary Gland / Q000737:chemistry*; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D017481:Receptors, Somatostatin / Q000235:genetics*
D012333:RNA, Messenger; D017481:Receptors, Somatostatin