Abstract
The ability of eighteen analogs of LH-RH to inhibit LH-RH-induced LH release was tested in primary cultures of rat anterior pituitary cells. [Des-His2]LH-RH, [Des-His2, D-Leu6]LH-RH and [Des-His2, D-Phe6]LH-RH inhibited 50% of LH-RH-induced LH release at molar ratios (MR50s) of 3000, 500 and 60, respectively, while [D-Phe2]LH-RH, [D-Phe2, D-Leu6]LH-RH and [D-Phe2, D-Phe6]LH-RH had similar effects at MR50s of 1000, 150 and 25, respectively. This indicates that substitution of D-phenylalanine for histidine at position 2 of LH-RH leads to compounds approximately 3-fold more potent than the corresponding [Des-His2]-analogs. [D-Phe2, D-Phe6]LH-RH, the most potent antagonist tested has however a slight agonistic activity (0.003% that of LH-RH itself). [D-Phe2, D-Phe6, Phe7]LH-RH, [D-Phe2, Phe3, D-Phe6]-LH-RH and [D-Phe2, Phe5, D-Phe6]LH-RH inhibit 50% of LH-RH action at MR50s of 400, 100 and 75, respectively. All of the analogs mentioned in the last group have LH-releasing activities below 1/100,000 that of LH-RH itself.
Original language | English (US) |
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Pages (from-to) | 201-208 |
Number of pages | 8 |
Journal | Molecular and Cellular Endocrinology |
Volume | 5 |
Issue number | 3-4 |
DOIs | |
State | Published - Jan 1 1976 |
Externally published | Yes |
Keywords
- antagonistic analogs
- cell culture
- LH
- pituitary
ASJC Scopus subject areas
- Endocrinology
- Endocrinology, Diabetes and Metabolism