Evaluation of the gonadotrophic responsiveness of the pituitary to acute and prolonged administration of LH/FSH-releasing hormone (LH-RH) in normal females and males.
In normal females, the injection of 25 microgram of LH-RH (acute test) induced a greater LH and FSH release from the pituitary in the mid-luteal than in the mid-follicular phase of the menstrual cycle. In normal males, the responsiveness to 25 microgram LH-RH was greater than that in females at mid-follicular but not at the luteal stage. The pituitary response to the prolonged LH-RH infusion (0.21 microgram/min/8 h) was similar in both phases of the cycle of the females with a decline in serum gonadotrophins after the 4th hour and was paralleled by a significant increase of plasma oestradiol levels. In males the LH, but not the FSH secretion was lower as compared to female subjects, and gonadotrophin levels did not show a fall during the infusion. The acute injection of 25 microgram LH-RH at the end of a prolonged infusion induced the same response in the female subjects in both phases of the cycle. In males, the acute test following prolonged infusion produced a similar LH secretion, but a lower FSH response than in females. The comparison of the acute test alone and that preceded by a prolonged LH-RH infusion, demonstrated that, in females, the only significant differences consisted of a greater LH secretion in the former test in the mid-luteal phase. In males there was greater FSH secretion in the acute isolated test than when this test was given after the prolonged infusion.
D000328:Adult; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood / Q000378:metabolism*; D005498:Follicular Phase; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage; D006801:Humans; D007263:Infusions, Parenteral; D007275:Injections, Intravenous; D008183:Luteal Phase; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D008297:Male; D010903:Pituitary Gland, Anterior / Q000378:metabolism* / Q000502:physiology; D013739:Testosterone / Q000097:blood
D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone