1. Opioid modulation of LH secretion by pig pituitary cells in vitro
- Author
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John B. Barrett, J. T. Wright, C.R. Barb, Robert R. Kraeling, and George B. Rampacek
- Subjects
Embryology ,medicine.medical_specialty ,Pituitary gland ,Time Factors ,Swine ,(+)-Naloxone ,Biology ,Basal (phylogenetics) ,Endocrinology ,Internal medicine ,medicine ,Animals ,Secretion ,Opioid peptide ,Cells, Cultured ,Dose-Response Relationship, Drug ,Naloxone ,beta-Endorphin ,Obstetrics and Gynecology ,Cell Biology ,Luteinizing Hormone ,medicine.anatomical_structure ,Reproductive Medicine ,Opioid ,Pituitary Gland ,Female ,Pituitary Hormone-Releasing Hormones ,medicine.drug ,Hormone ,Endocrine gland - Abstract
The effects of naloxone and beta-endorphin on LH secretion by pig pituitary cells were studied in primary cultures. On Day 4 of culture, cells (10(5) seeded/well) were challenged with 10(-9), 10(-8) or 10(-7) M gonadotrophin-releasing hormone (GnRH), 10(-10), 10(-9), 10(-8) or 10(-7) M-beta-endorphin or 10(-6) M-naloxone individually or in combinations. Secreted LH was measured at 4 h and 24 h after treatment and cellular content of LH was measured after 24 h. Basal LH secretion (control) was 23.5 +/- 7.6 and 36.9 +/- 10.3 ng/well at 4 h and 24 h, respectively. Relative to control at 4 h, 10(-9), 10(-8) or 10(-7) M-GnRH stimulated (P less than 0.05) LH secretion 140%, 210% and 250%, respectively. At 24 h, LH secretion was increased (P less than 0.05) by GnRH compared to control, but the dose-response to GnRH was absent. Naloxone increased (P less than 0.01) LH secretion 166 +/- 13% at 4 h and 141 +/- 13% (P less than 0.06) at 24 h. Secretion of LH after simultaneous addition of 10(-8) M-GnRH plus naloxone was greater (P less than 0.01) than after GnRH alone at 4 h but not at 24 h. beta-Endorphin at 10(-10), 10(-9), 10(-8) or 10(-7) M failed to alter basal LH secretion at 4 h but decreased secretion at 24 h, while cellular LH content was similar to control at 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)
- Published
- 1990