Effects of changes in pattern of LHRH pulse on LH secretion by perfused anterior pituitary cells of male rats.
In the present study, a perfusion system of dispersed cells was used to investigate the effects of LHRH pulse amplitude and frequency, and LHRH continuous stimulation on LH secretion by anterior pituitary cells of adult male rats. The results have shown that, in the range of LHRH concentrations from 1 X 10(-10) to 1 X 10(-6) mol/L, the dose-response curve of LH secretion was linear. LHRH pulse frequency generated a biphasic LH response: increasing LHRH pulse frequency increased the basal LH secretion and decreased LH/pulse. When 1 X 10(-9) mol/L or greater LHRH was given at frequencies of 3 pulses/h or higher, it was observed that a maximal LH peak was induced and then the LH release declined progressively to its LH basal level, i.e. LHRH self-priming effect and LH desensitization occurred. Enhancement of amplitude of LHRH pulses could reduce pulse frequency required for priming. Increases in frequency of LHRH pulses with high amplitude would provoke the priming effect more quickly. In addition, continuous perfusion of LHRH with different concentrations could also elicit the LHRH self-priming effect and lH desensitization. LHRH with low concentration (1 X 10(-10) mol/L) would take much longer to evoke a self-priming effect. These results indicate that the LH secretion pattern is dependent on LHRH pulsatile amplitude and frequency, and will help to clarify the kinetics mechanisms by which LH pulses fluctuate in vivo.
Qu
Z C
ZC
Sichuan Family Planning Research Institute, WHO Collaborating Centre for Research in Human Reproduction, Chengdu, PRC.
Yu
J H
JH
Guo
J
J
Guo
J
J
D000818:Animals; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000378:metabolism*; D008297:Male; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone